More than anything else, it’s momentum that makes tennis so nerve-wracking to play. Or, I should say, it’s the fear of momentum. No matter how far ahead you are, every time you lose a point something in the back of your head wonders whether it might end up being the spark your opponent needed to turn everything around. It’s brutal: You can’t relax for a second.

For anyone who knows that feeling, watching the 2009 U.S. Open men's final—No. 5 on my most-memorable list for the year—was like seeing your worst nightmare come to life. Here we have Roger Federer, a 15-time Grand Slam champion with a perfect record against his opponent, Juan Martin del Potro, who is making his major-final debut. Federer plays some of the best and most dominating tennis of his career through the first set and a half. He serves for a two-set lead and a seemingly insurmountable edge. But he doesn’t put away a short ball in that game, del Potro comes up with two brilliant passes, and a couple hours later Federer is shaking hands a loser, his five-year win streak at the Open a thing of the past. Let's take a look at the brutal details. (The clip above covers the first half of the match. For the rest, click here. I wasn't able to embed it on this page.)

—Federer is a fast starter in U.S. Open finals. In the six he’s played, he’s won the first set all six times, including a bagel over Lleyton Hewitt in 2004. Something about the quick surface and the heightened late-Sunday atmosphere inside Ashe Stadium must agree with him. He jumped out as quickly as ever against del Potro, going up 3-0 and making a stunning crosscourt forehand pass after running all the way across the baseline in the process. The first del Potro highlight in this clip doesn’t come until 1-2 in the second set, when he’s already down a break.

—To start, Federer seemed to be trying to work his inside-out forehand to del Potro’s backhand, and he had it lasered right onto the sideline. He also continued the strategy of bringing del Potro in that had worked so well in the French Open semis. For a set and a half, it looked like this was going to one more lesson from the master.

—A key moment that was lost in the shuffle: Del Potro goes down 1-3 in the second and faces a break point at 30-40. This is essentially a set point for a two-set lead for Federer. But del Potro gets in a strong first serve to Federer’s backhand, follows it with a forehand winner, and grunts in self-approval. He’s more famous for his killer forehand, but del Potro’s ability to step back and get in big first serves when he’s down break point is just as important to his game. After that point, the famous forehand started to flow.

—From there, it’s heavy artillery time. These guys’ shots come so fast and deep, they seem to pick up speed as they go. Jimmy Arias has said that del Potro is one of the few players who hits hard enough to throw the nimble Federer off balance. Watching from the sideline at this match, I would say that del Potro is the first guy I’ve seen who hits hard enough, with enough depth and low-trajectory penetration, to keep Federer from leaning into the court and creating the way he usually does. From a court-level perspective, the physical difference between the two was striking. Del Potro seemed to be wearing Federer down and pushing him backward—almost looming over him from the other side of the net. After the second set, it seemed to me to be only a matter of time before del Potro would win the match; Federer actually made it much closer than I would have anticipated. But he couldn’t hold him off in the fifth. I’ve heard that Federer thought he choked this match in the end, and I’m not going to argue with him. But it looked to me like trying to hold off the del Potro onslaught finally made Federer's own strokes go haywire.

—At the same time, I don’t think Federer gave himself the best tactical chance to win. Rather than continue to go inside-out to del Potro’s backhand, he started going inside-in to the forehand. And del Potro began to read it. In a big way. But even after DP had clearly found his range with his crosscourt forehand slap shot—the ball comes off the court like a puck off ice—Federer didn’t shift his aim toward the backhand. Afterward, Federer maintained that del Potro’s backhand is his more dangerous shot. Was there a hint of the fabled Federer stubbornness in this strategy?

—Have to love the del Potro player box. A coach, a trainer, an agent, and a bunch of empty seats. Why do need anyone else?

—Del Potro held his nerve admirably for a Slam-final rookie. The transcript of Federer’s press conference afterward has him saying that DP kept a “steel racquet” in the clutch. Sitting in the presser, I heard it as “still racquet,” which would make more sense—Federer was saying that del Potro had done a good job of keeping his nerves a bay. Look at the last point. DP hits a bullet forehand down the line that Federer somehow scrapes back over the net and drops into a difficult position short and low. But del Potro is there to dig it out and send another tremendous forehand up the other sideline for the match. He earned it.

—I’ll finish with my finishing words the day after the match:

Walking through Flushing Meadows afterward, there was a buzz in the air that I was going to miss. I couldn’t believe it, but I suddenly wanted to see more tennis. I got on the train back into Manhattan. The woman sitting next to me, who was coming from farther out on Long Island, asked, “Did you see del
Potro?”

“Yes, I saw him.”

“I liked to watch him when he won,” she said, and she put her hands over face, imitating del Potro’s emotional reaction after the final point. She’d hit it: That was why I wanted the Open to keep going. I wanted to see that emotion and relief that only a player who has won his first Grand Slam can conjure. It doesn’t happen all that often nowadays, which only made the last moments of yesterday’s final that much more exhilarating. Thanks for sharing it with us, Juan Martin.

In my last post I stated that 2009 was a good year for tennis matches. Unfortunately, I realize now that I need to revise that assertion: It was a good year for men’s tennis matches. From a competitive standpoint, the women disappointed. Dinara Safina came up lame in both the Aussie and French finals, the Williams sisters gave us a briefly compelling but ultimately unmemorable Wimbledon final, and Caroline Wozniacki couldn’t quite make herself into a threat to Kim Clijsters at the U.S. Open.

That leaves us with just one WTA match that combined the requisite drama and excellence to qualify as a classic: the Wimbledon semifinal between Serena Williams and Elena Dementieva, won by Williams 6-7 (4), 7-5, 8-6. Above are a pair of highlight clips that cover much of the second and third sets. I apologize for the irritatingly excitable announcers—NBC pulled all the videos of its broadcast. But there’s no way to ruin this one. The tension builds right to the final point.

—I normally think of Serena as being a fierce competitor rather than an elegant one. Maybe it’s the traditional clothes or the Wimbledon setting, but from the start her strokes and movement seem smoother and more polished. Her extension through her forehand in the first few rallies shown is exemplary. She also seems to be hitting it with more topspin than usual, and with a concerted effort to pin Dementieva deep in the court. You can see that Serena is in a no-nonsense mood.

—Dementieva is counterpunching for the most part. Her game has always seemed to me to be the tennis equivalent of a blind person who has, in order to survive, developed her other senses to their maximum. Dementieva’s blind spot—her serve—has forced her to become just a shade quicker along the baseline, make her strokes a little more compact, and tighten up her reaction time. She’s had to deal with fending off big returns her whole career, which helps her come in prepared for Serena’s rockets. Sometimes Dementieva looks more like a hockey goalie out there than a tennis player.

—Hawkeye was cruel to the Russian in this match. The machine made two calls against her by the barest of margins.

—There are few Hall-of-Famers who are as willing as Serena Williams to do anything to stay in a point the way she is. If she’s pushed to her right, she’s not embarrassed to go to the hack slice forehand and pop it straight up in the air, if that’s what it takes to get the ball over the net.

—Dementieva certainly had her chances. She blew an open-court backhand in the last game of the second set that I believe would have gotten her to a tiebreaker. But the most telling moment for me comes when she goes up a break in the third, 3-1. Immediately, she drills two very makeable forehands into the net. Dementieva likes pace; the more time she has, the nervous she can get, especially in this situation against Serena. Also, does Dementieva not move forward that well? On one point she's unable to take advantage of a weak Williams return because she can’t get there in time.

—Dementieva has match point at 5-4 in the third. Serena hits a mediocre serve and Dementieva hits a solid backhand return. You think it will be a typical rally, but Serena decides to take the initiative right away. She doesn’t do anything spectacular, but she does force Dementieva to come up with a backhand pass. The Russian mistakenly chooses to go crosscourt, where Serena is waiting. Fortune in tennis still favors the brave. And the good.

—This match reaches its peak with Serena serving at 5-6 in the third. There's lots of desperate hitting and desperate emotion: Dementieva is left down for the count after one point, and Serena gets right in her face on another. Most crucial, Serena hits two aces to rescue herself. In the next game, her ground strokes land on the baseline multiple times, including twice on the final point. Not surprisingly, she breaks serve. Fortune favors the brave, the good, and the fortunate.

—For such a tense match, it ends in an odd way. You rarely see a player miss the last ball of a tight contest by going for winner and sending the ball wide. It’s easier to gauge the sideline and find the right margin for error than it is to gauge the baseline or the net—with the match on the line, why aim so close to the sideline? But Dementieva does just that and strokes the last ball wide. It's almost as if part of her has decided that destiny is against her on this day, at this event, against this opponent.

—With Dementieva serving as well as she ever has, there was almost nothing to separate these two players. Every set was close, every game hard fought. Why did Serena win? There’s her serve, of course, and her power, and her speed. But what comes to my mind is the way she reacts to her missed shots, as compared to the way her opponent reacts.

Serena can’t believe she can miss. She can’t believe she can lose. Dementieva, as much as the thought upsets her, can.

Yesterday at ESPN.com I wrote that 2009 was all about the trophy ceremony. “God, it’s killing me.” “I’m one of the lucky few who gets cheered for.” “My lovely wife, who’s pregnant!” “We were yoking…” Whatever del Potro said in Spanish at the Open. In 2009, the Emotional Generation soared to new heights on the Grand Slam winners’ stands.

Nowhere was this truer than at the Australian Open. The now-immortal tears and words of Roger Federer and Rafael Nadal will forever overshadow what was, on second look this morning, a sizzling tennis match that might have defined this era, if Federer and Nadal hadn’t already done that the year before at Wimbledon. Only Federer’s final set collapse, which is largely absent from the highlights above, keeps me from rating it higher than No. 7 for the season. It was a good year for trophy ceremonies, but it was a good year for matches as well.

—Federer starts out hot, hitting some outrageous winners reminiscent of his best stuff from Wimbledon 2008. But even in this very early stage, where he is controlling the action, is there a sense that he’s pressing more than he presses against anyone else? As someone wrote about Jimmy Connors when he played Bjorn Borg in one of their Slam finals, Federer’s winners should count for two points each—that’s how big a risk he’s taking with them. But that's also because Nadal is pushing him out of the middle of the court and forcing him to take chances.

—The revelation, though, is Nadal. Is this the same guy who finished the season in such tame and dispirited fashion? Here he's up on the baseline, pushing Federer off the center hash mark, outfoxing and out-varying him with drop shots, on-the-run reflex winners, and short-angle volleys, and playing with that famous determined kick in his walk and snarl on his lip. He’s also changing directions with both strokes much more often than I recall. The biggest difference, though, is that Nadal’s backhand is a weapon. I haven’t seen that full-swing, up on his toes, sharp crosscourt two-hander in months. I seem to remember he tried it when he had a break point in the final game of the Madrid final against Federer and missed it wide. (I remember it because I’ve never felt the air go out of a building the way it did when the ball landed in the alley.) Did he make that shot again in 2009?

—These were still the days when the only question worth asking in tennis seemed to be, “Why doesn’t Federer come in against Nadal?” The answer is right in front of us here: Because Nadal, at his best, can hit a passing shot on a dime, from either wing, from any spot on the court, with frame-shaking topspin. You try to come in against that 50 times in a match.

—These were also the days when Nadal was routinely outplaying and outhitting Federer when it mattered most. Look at the point he constructs on set point at 6-5 in the first set. Nothing defensive about that. Even better, look at the rally he constructs on what would prove to be the most important point of the match, at 5-3 in the third-set tiebreaker. For most of these five sets, he stood at the center of the court and hit his forehand forcefully but safely crosscourt, to a spot just behind the service line and well within the sidelines. The fact that he can tilt the rallies this way and dictate them without much risk has always been the fundamental reason he owns a 13-7 record against Federer. But at 5-3, when he knew that a winning point would put him in position to take a two-set-to-one lead, but that a losing point would still leave him ahead 5-4, he moved his forehand target all the way to the sideline. Nadal hit that spot, made a rare dash to the net, and angled away a backhand volley. The set was his, and the lead was too much for Federer to overcome. For anyone who still thinks Nadal is “one-dimensional,” realize that he’s one-dimensional by choice. When he senses the right moment to do more, the resources are there and the surprise factor is built-in.

—And then it’s all drowned out by the ceremony afterward, which is what the world will remember from this day. We all know what happened, but seeing it again I’ve found my two favorite moments. The first is the earnest ovation that Nadal gives Federer from behind him as Federer is beginning to lose it. Nadal pushed the joy of winning the Australian Open all the way down inside him and became instead a respectful and concerned friend. Do you resent that Federer in a sense stole some of Nadal’s thunder? You shouldn’t: He inadvertently brought out a gracious and gentlemanly side of the Spanish kid that many tennis fans didn’t know existed below the biceps and fist-pumps. Even on the trophy stand, Federer brought out the best in Nadal.

The second moment is the look on Federer’s face when Nadal finally gets him to smile and walk back up to finish his speech. The greatest tennis player of all time looks, at that moment, like a nice, embarrassed kid—a nice, embarrassed kid we’ve all been at one time or another.

No wonder we like these two guys so much.

In the first two matches on our Best of ’09 list, I’ve prefaced the discussion by saying that from a quality of play perspective, they left something to be desired. I’m not sure you can say that for No. 8: How much better can the quality be when 78 of its points are won with a single perfect shot, and that the guy hitting them comes up second-best?

What you can say is that Radek Stepanek’s 6-7 (5), 7-6 (5), 7-6 (6), 6-7 (2), 16-14 win over Ivo Karlovic in the semifinals of Davis Cup won’t be forgotten any time soon. Karlovic’s 78 aces, which is 23 more than his previous record, is a mark that’s going to be in the books for a while—unless Dr. Ace himself breaks it, that is. The match's length, 5 hours and 59 minutes, and total games, 82, are just short of being all-time records themselves. And can a contest be any closer? The fourth set, which Karlovic won 7-2 in the breaker, must have felt like a blow out.

The first time I posted about this match I showed an eight-minute You Tube clip of Karlovic’s 78 aces. Now they’ve been whittled to a much crisper and more convenient 2 and a half minutes. The person who put it up, Magnificat3, has also tracked the directions of Ivo’s bombs: 39 went past Stepanek’s forehand, 39 went past his backhand. What Karlovic’s height gives him is the ability to ace his opponents anywhere, including with a flat bomb out wide that lands way up the sideline. He’s the only person I’ve ever seen hit that serve. And his smooth, bare-bones delivery must be next to impossible to read. You can see that on a lot of these serves, Stepanek guesses the wrong way. Watching them go by him one after the next is comical. I start to crack up right around the one-minute mark.

What we don’t see is how Stepanek hung in to beat him; all we get here is the Czech looking helpless, until, on the final point, he wins the whole thing. One clue to his victory is that he seems to take all of Karlovic’s aces in stride. He knows they’re going to happen sooner or later (or always), and it will only hurt him to get upset about it. Whatever he did to keep himself in it—I only saw the final set—Stepanek’s achievement is one of the finest of the year. He survived three sets worth of aces.

The other moment we don’t see is the aftermath. Stepanek was overcome as he slowly moved from one of his teammates to the next and eventually into the Czech section of the audience. Karlovic, as usual, looked utterly alone. This is what I wrote the first time I posted about his defeat:

Karlovic’s freakishness has never come across as painfully as it does here, when he walks off the court a loser after six hours. He takes it as impassively as always. It’s as if he realizes he’s a guy not destined for glory, even in Davis Cup, a place where second-tier players like him are traditionally allowed to shine for a few moments. Instead, he’s destined to be good enough, in a weird enough way, to set a monumental record even while suffering the most heart-breaking loss of his career. Tennis has feared the rise of the big server for decades, but Karlovic proves again that these fears remain unfounded. If this performance showed us anything, it's that tennis still can’t be won with one shot alone. The sad thing for Ivo is that the sport is better off with him as a loser. At times, when I see how glum and lonely he can look on a court, I think he knows this.

The ninth most memorable match of 2009 might also qualify as the most unlikely of the year. It involved that rarest of tennis finds, a Spanish server and volleyer, trading forays to the net for five sets against a guy who had recently been on the verge of settling into his second career as a teaching pro. It was so unlikely that, despite the fact that it took place on my favorite court, the Grandstand at the U.S. Open; despite the fact that I suspected that the ex-teaching pro in question, Taylor Dent, might set off a few fireworks around Flushing this year; and despite the fact that I was walking past that court as the match was starting, I was not in the arena to see it. I went home and, kicking myself the whole time, watched it like everyone else on the tube. I could feel the electricity all the way from Queens.

Watching the fifth-set tiebreaker in this second-rounder between Dent and Ivan Navarro, it’s clear that, like the Oudin-Sharapova match from yesterday, this wasn’t a classic for its quality. There are a lot of tight volleys, blown sitters, and ill-advised line-call challenges. But the key word in that sentence is volleys. If this match didn’t prove that serving and volleying can still get you deep into a major—Dent was beaten soundly by a baseline-hugging Andy Murray in the next round—it did remind us that constant net-rushing can still produce uniquely hair-raising tennis. Especially when it’s done by an American, at night, in New York City.

—We begin with an Aussie commentator noting that Dent uses one racquet for serving and another for returning. I don’t think I’ve ever seen this before. The announcer speculates that it’s because he strings one of them a little looser. Whatever the benefit, it’s got to be hard to adjust your swing on ground strokes each game. I guess Dent figures he hits mostly groundies when he’s returning, and mostly volleys when he’s serving.

—It’s hard to believe with this energy and atmosphere, but the stands aren’t full. Some tennis traditionalists might find the crowd, with its zealous partisanship, its random bursts of noise, and its sloppy summer fashion, to be of the Ugly American variety. But I’ll bet you would have liked to have been there, too. Isn’t it a strength of the sport that it can be played in places as varied as Wimbledon, Paris, and Flushing Meadows?

—I don’t think I’d seen Navarro before this. He seems like not just an old-school player, but an old-school doubles specialist. As they used to teach you in dubs, he kicks his first serve in and gives himself time to close on the net. His forehand volley is strange and stiff, but he’s so far up in the court that Dent still has trouble doing much with it.

—Up close, Dent isn’t as big as you might think. He’s also a mellow guy without the sense of entitlement that you normally expect from a professional tennis player. I always wondered if that was part of his trouble. He didn’t need to win to satisfy his ego or his sense of himself.

—Would the sport be better if there was more of this type of tennis? Undoubtedly. For one thing, s & v doesn’t need to be of the same astounding quality as the best baseline tennis to still be entertaining. If it lacks the head-smacking wow factor of a winner drilled from behind the baseline, s & v makes up for it in the relentless, nerve-wracking pressure it creates. Pressure on the returner to keep the ball low. Pressure back on the volleyer to make a lightning-quick reaction and decision at the net. Pressure back again on the returner to make a clean pass, because he’s probably going to get one shot at it. It’s tennis played at a different tempo, both for players and fans. The compression of the points, especially in tiebreakers, especially in fifth-set tiebreakers, gives the sport an antic energy. It also imposes more logic on the proceedings. Rather than rallies that end in errors for no particular reason, there's always a cause and effect with the serve and volley game.

—I love Dent’s overamped reaction at the end. His appreciation of the atmosphere on the Grandstand makes you remember that this tournament is not the norm in the pro game. The Open still lives up to its rowdy reputation. Dent is so psyched up by it that he can’t think of how to end his speech into the chair umpire’s microphone. So he skips the “thank you” and comes up with the only appropriate words for the moment: “Let’s go!”