The ranks of Americans remaining in the French Open were winnowed from four to three Sunday as Lindsay Davenport, the fifth seed in the women's draw, was ousted by Russia's Elena Dementieva.

Davenport, who has won three of the four major tournaments that make up a career Grand Slam, underwent knee and foot surgery in the past two years in hopes of extending her career and, ideally, claiming the one title that eluded her: the French Open.

But early in the second set of her fourth-round match against Dementieva, she heard a disquieting pop in her right knee and never moved freely after that, succumbing in short order, 6-1, 6-3.

Meanwhile, Venus and Serena Williams advanced with ease to the quarterfinals, and Jennifer Capriati managed to compose herself after an erratic first set against Italy's Francesca Schiavone to join the sisters in the round of eight.

Of the bunch, Venus Williams is playing the best tennis. She has yet to drop a set, though Colombia's Fabiola Zuluaga came close Sunday before falling, 6-1, 7-6 (7-3).

"Today I had the opportunity to close it out fairly easily, but missed some shots that I shouldn't have missed," Venus Williams said. "Next thing you know, the match is closer."

Serena Williams, the 2002 French Open champion, beat Japan's Shinobu Asagoe, 6-3, 6-1, in 55 minutes. It was an impressive showing, but Serena insists her game isn't as sharp as she would like following an extended break from the women's tour.

The women take Monday off, yielding the Roland Garros show courts for the men's quarterfinals. When they return to action Tuesday, three Americans, three Russians, an Argentine and a Frenchwoman will compete for semifinal berths.

Serena Williams, the highest seed remaining (No. 2), will face a loose and apparently carefree Capriati, whose confidence was buoyed by a victory over Serena two weeks ago in Rome.

"I feel like if I can just keep the balls in play, I think that I should have the edge a little bit," Capriati said, "because she's still kind of not used to playing on clay."

Venus Williams plays Russia's Anastasia Myskina, the sixth seed. If the sisters advance, they would meet in Thursday's semifinal.

The other half of the women's draw appears neatly paved for France's Amelie Mauresmo's march to the championship. Mauresmo rolled over Magdalena Maleeva, 6-2, 6-1, and squares off Tuesday against the quirky-serving Dementieva.

The other quarterfinal pits No. 14 seed Paola Suarez of Argentina against Russia's Maria Sharapova.

Roland Garros, host of the world's most prestigious clay-court tournament, has been inhospitable to Americans this year. All 10 American men in the 128-player draw were defeated in the first three days. The American women have fared better, but Davenport's loss was particularly disappointing given the injuries she has slogged through and the short amount of time that likely remains in her career.

She planned to fly home to California Sunday night and didn't expect to have a diagnosis on what is ailing her knee for a few days. "I'll be extremely bummed if it means more time away," said Davenport, who turns 28 next week.

Davenport's serve-and-volley game is ill-suited to clay. And the chilly, damp, overcast conditions that crept into Paris Saturday night only made matters worse. The air was thick and humid. The red clay was slow. And the balls were heavy, dropping with a thud on the soggy playing surface.

Davenport started slowly, allowing Dementieva to close out the first set in 21 minutes. But she was reasonably confident she could get back in it until she landed slightly off balance on her right knee and heard something click inside.

Nothing felt right after that -- not her knee, not her confidence, not even her common sense. She thought briefly about withdrawing from the match to avoid risking further injury, but she didn't want to do that, having been forced to retire from the tournament with a foot injury the previous year. Then again, she didn't want to just stay out there playing lousy tennis. So she muddled through as best she could.

"I just decided to keep the points short -- go for just weird shots and see what happens," Davenport said. Her risk-taking, combined with some unforced errors and four double faults on Dementieva's part, helped Davenport win three games in the second set. But it wasn't enough.

"I don't know what it accomplished," Davenport said of her decision to continue playing. "It's just so frustrating that you're not given an opportunity physically 100 percent out there. It's tough enough to deal mentally with everything -- sometimes bad play, sometimes great play. But to be able to be not hurt would be very nice."

"It's just so frustrating," Lindsay Davenport said of re-injuring knee, which left her unable to overcome early deficit in 6-1, 6-3 loss to Russian Elena Dementieva.