NEW YORK -- If someone is going to beat the Williams sisters here at the U.S. Open, it will have to be someone other than Jennifer Capriati.

	Jennifer Capriati says she got 'tight' when playing Amelie Mauresmo.

That nasty little job has been left to either Amelie Mauresmo -- who stunned the sulking No. 3 seed here with an improbable three-set comeback 4-6, 7-6 (5), 6-3 on Wednesday afternoon -- or the still-recovering Lindsay Davenport in the semifinals. Each faces a Williams sister.

Capriati was the feel-good sports story of 2001 when she returned from personal oblivion and won the Australian Open and French Open. But, for the first time, she admitted Wednesday to feeling the pressure that comes with three Grand Slam titles and the world's No. 1 ranking. Capriati was actually serving for the match at 6-5 in the second set, when she, well, choked.

Later, Capriati said so, not in quite so many words.

"There was a moment when I relaxed when I got ahead," Capriati explained. "But, you know, just when I was serving for it, I felt like all of a sudden, I just got really nervous and just really tight."

A queasy double fault gave Mauresmo a 15-30 lead and a loose, lazy (and long) forehand -- one among many -- lifted the Frenchwoman into a tiebreaker, which was the beginning of Capriati's demise.

"There's a difference between wanting to (win), and then expecting yourself to and thinking that you should be up there," Capriati said. "Of course, a lot of other people think I should be up there. So it plays a part.

"It's something that I haven't really felt in a while, and maybe I've been feeling it more lately."

Athletes choke under pressure all the time, but rarely do they admit it. At the end of her press conference that had been marked by a variety of sullen replies, Capriati was asked to clarify her use of the word "tight."

She seemed amused by the question.

"Well, I think getting tight is basically saying you choked," Capriati said, getting up to leave. "So ... basically..."

The reporters gathered in the interview room had the good grace to laugh. But Capriati's exit raised far more questions than her answers satisfied.

To break it down: Capriati, who won this year's Australian Open after saving four match points, is the only non-Williams to come out of the last nine Grand Slam singles events with a trophy. Venus Williams (4) and Serena (2) are the only others on the board.

So if Capriati is feeling the heat, if she is ready to check out after -- "being No. 1 and having such a great run" -- who will challenge the Williams sisters?

It may be a moot point, but Mauresmo is as good an answer as anyone else. Davenport is still coming back from knee surgery and seems genuinely happy to be in the semifinals against Serena Williams. Mauresmo, who draws older sister Venus, would seem to have a marginally better chance of winning.

At least on Wednesday, there was something about Amelie.

Previously, Mauresmo, 23, was known for her broad shoulders, elegant backhand and an affinity for tightening up when the points matter most. Mauresmo, who is listed at 5-foot-9, 141 pounds, is one of the few players who can trade deep, thumping groundstrokes with Capriati. She had already split six previous matches with Capriati, including winning the past two this year at Wimbledon and Montreal.

Still, early on it became apparent that pace and power were not going to be her modus operandi. Instead, Mauresmo spun the ball -- stylish slices and looping topspins -- and over time the historically impatient Capriati began to break down.

"She likes to play with a lot of pace and same height," Mauresmo explained later. "When you slice a little bit, and you put some topspin, maybe she's not used to that. Because on the Tour, not so many players play like this.

"I know that's what she doesn't like too much. I try to do that."

	Amelie Mauresmo might be the woman with the best chance to stop the Williams sisters.

Mauresmo played to form in the first set, however, double-faulting on break point at 4-all. That essentially gave Capriati the set and, when she reached 6-5 in the second, seemingly the match.

"Yeah, I thought, 'OK, it's not my day. I'm going to go back home tonight,' " Mauresmo said. "But it happens. I mean, that's not because I think that I'm not going to fight or that I'm going to go out of the match.

"But, yeah, when you're down a set and 6-5 and she's serving, it's -- you know, hang in there, even though you're thinking maybe it's the last game."

After giving away that 12th game, Capriati went quietly in the tiebreaker. Mauresmo, visibly gaining confidence, began coming to net more often and, more important, she really started getting inside Capriati's head by messing with her serving rhythm.

When Capriati is going well, she serves quickly. Knowing this, Mauresmo would hold her hand up when Capriati was about to toss the ball.

"I needed to recover because she makes you run a lot," Mauresmo said. "But that's the game. If I need some times, I can have. If I need it, I'm going to take it."

Whether or not she took it in the third set or Capriati simply gave it, isn't important. Despite the fact they each won 106 points in the match, Mauresmo was bigger on the big points.

At 1-all, Capriati threw in a double fault and another aimlessly long forehand. At 3-5, she fought off four match points but still double-faulted twice. When one last forehand sailed past the baseline, Mauresmo -- who made the quarterfinals here a year ago -- had reached the semifinals of a Grand Slam for only the second time. Her first berth, at the 1999 Australian Open, happened to be the last Grand Slam won by Martina Hingis.

And when it was over, after Mauresmo had touched her fist to her chest as an acknowledgement of her terrific heart, Capriati seemed genuinely baffled.

"I should have come out and won that match," she said. "I had that match."

What, exactly, did she do wrong?

"Right now, I can't comment a lot about what happened in the match," Capriati said. "I haven't had enough time to really think about it.

"It's just something that I got to go and look at."

Greg Garber is a senior writer at ESPN.com.