In a showdown between two women who've been ranked No. 1 and own a total of nine Grand Slam titles, the top-seeded Mauresmo won nine of the last 12 points Monday night to beat the unseeded Williams 6-4, 0-6, 6-2 and reach the U.S. Open quarter-finals.

``I could have came out on top had I made a few more shots and had I just been a little bit more consistent,'' said Williams, who didn't think her recent lack of matches was a factor. ``Maybe a little bit more fire or something.''

In the second set, Williams looked on her way to improving her career record against Mauresmo to 10-1. But the outcome turned at 3-2 in the final set, when a 35-stroke exchange ended with Williams pushing a backhand into the net, then pausing for air.

That sent Mauresmo on her way to a key break _ and Williams wouldn't win another game, saying later: ``Just fell apart after that.''

On match point, they engaged in a 24-stroke rally that Mauresmo ended with a sharply angled volley Williams couldn't get to in time.

``I don't think she picked up her game 1,000 per cent or even that much,'' Williams said. ``I just think that she cut back on the errors.''

Williams came to Flushing Meadows having played only 12 matches all season because of a six-month break she used to rehab her surgically repaired left knee and to refresh herself mentally, too. During the time off, Williams tumbled out of the top 100 in the rankings, and needed a wild-card invitation to play at the Open.

If there have been questions about Williams' health and preparation of late, Mauresmo has been steadily erasing the doubts about her mental toughness. She didn't win any of her first 31 Grand Slam tournaments, but she's now closing in on her third such championship this year, after the Australian Open and Wimbledon.

``The experience I've got really helped me tonight,'' Mauresmo said. ``It's starting to show a little bit on the court.''

That was certainly the case the way she hung in there after a disastrous second set. Mauresmo lost 20 of the set's first 26 points and finished with one winner. But she regrouped in the third, while seven-time major champion Williams appeared to tire, and the Frenchwoman began controlling the tempo the way she had early.

Mauresmo wrong-footed Williams with groundstrokes and gave her fits by mixing speeds and spins. One example: Mauresmo broke to end the first set by launching a high-bouncing shot that Williams' backhand couldn't handle, sailing the ball wide.

With that, Mauresmo raised a fist, clenched her jaw and jogged to her sideline seat. Williams walked over slowly, her sister Venus (sidelined with a wrist injury) and mother looking on from the guest box, while her father snapped photos from elsewhere in the stands.

Now Mauresmo plays No. 12 Dinara Safina, whose path to the final eight hasn't included a match against a seeded player.

The match under the lights at Arthur Ashe Stadium brought back some electricity to a tournament that felt a bit Monday afternoon like a party carrying on after the guest of honour has left. The U.S. Open did indeed proceed without Andre Agassi, although a fan cried out, ``Do it for Andre!'' during Andy Roddick's fourth-round match.

Roddick obliged, putting together a 6-3, 6-4, 6-3 victory over Benjamin Becker, the German qualifier who ended Agassi's career the day before.

Roddick and No. 5 James Blake, whose fourth-round match against No. 12 Tomas Berdych is Tuesday, are the only U.S. men left in the tournament. No. 18 Robby Ginepri bowed out with a 7-6 (1), 6-4, 3-6, 3-6, 7-6 (1) loss to No. 14 Tommy Haas.

Haas next faces 2000 Open champion Marat Safin, Safina's older brother. Other past winners still in it are Lindsay Davenport and Justine Henin-Hardenne, who set up a quarter-final clash with straight-set wins. But 2004 Open champion Svetlana Kuznetsova is gone after losing to No. 19 Jelena Jankovic 6-7 (5) 6-3, 6-2. Also into the quarter-finals were No. 3 Maria Sharapova _ who lost the first three games before eliminating No. 24 Li Na of China 6-4, 6-2 _ along with 2004 runner-up Elena Dementieva.

Roddick won the 2003 Open but lost in the first round last year, part of a dismal stretch that briefly dropped him out of the top 10. Now he has Jimmy Connors as his coach and a 10-match winning streak.

``If you can't draw motivation from six months of bad results,'' Roddick said, ``then you're not going to draw it from much.''

His next foe is 2001 U.S. Open champion Lleyton Hewitt or No. 25 Richard Gasquet, who were to meet in Monday night's last match on Ashe. That main court was the scene of Agassi's last hurrah, a four-set defeat against the unheralded and 112th-ranked Becker on Sunday.

``It was tough yesterday for me to enjoy it, because it was tough for me to accept that I deserved to be the last guy that Agassi played,'' said Becker, competing in his second major. ``It's been a pretty, pretty amazing trip for me.''

He was physically and emotionally drained, but he might not have had much of a chance, anyway, given how well Roddick served. Roddick won 57 of 70 points in his service games, was stretched to deuce only once, and ended the first set this way: 137 m.p.h. ace, 100 m.p.h. ace, 145 m.p.h. ace, 142 m.p.h. service winner.

Roddick was a bit anxious about how things would go with Connors, who's been pretty much out of the game since retiring in the early 1990s. But Roddick uses words like ``refreshing'' and ``invigorating'' when discussing Connors' effect on him.

It's also been a thrill just to spend time with Connors, including when he stayed at Roddick's house in Austin, Texas.

``Maybe it's been a while since he's just been one of the boys, playing pool and poker and hanging out,'' said Roddick, on track for a semifinal against No. 2 Rafael Nadal, a 6-1, 7-6 (3), 6-4 winner over Jiri Novak. ``We'd practise, he'd come home, kick his feet up on my couch, have a beer. It was pretty surreal.''