WIMBLEDON, England -- Jennifer Capriati kept her Grand Slam bid alive Tuesday, rallying from the edge of defeat to beat Serena Williams in three sets and reach the semifinals at Wimbledon.

	Serena Williams despairs after being beaten by compatriot Jennifer Capriati in their women's quarterfinal match.

Just two points from losing in the second set, Capriati charged back to win 6-7 (4), 7-5, 6-3 and advance to Thursday's match against Justine Henin.

"It makes it that much sweeter to actually come back and win a match like that," Capriati said.

Henin, a French Open semifinalist, had a much easier time, beating 1994 champion Conchita Martinez 6-1, 6-0.

Serena's sister had a good day -- defending champion Venus Williams defeated Nathalie Tauziat 7-5, 6-1. Venus then went to Centre Court to watch her sister play her final points of the tournament. She'd like to draw motivation from the loss. "Let's hope so," said Venus, who lost four straight games, tying the first set 5-5, then won the next two. "If I can't do it for myself, I'll do it for (Serena)."

She'll play third-seeded Lindsay Davenport next in a rematch of last year's final. In 1999, Davenport beat Steffi Graf for the championship.

Davenport advanced with a 6-1, 6-2 win over seventh-seeded Kim Clijsters, who nearly beat Capriati in the French Open final before losing the third-set tiebreaker 12-10.

Capriati is trying to become the sixth person to win all four major events in the same year and the first since Steffi Graf in 1988. She won the Australian Open in January and the French Open in June. The U.S. Open starts in late August. Now she's just thinking about Wimbledon.

"There's still more obstacles coming," Capriati said, "the next match."

Henin could have some trouble in the semifinals besides Capriati. Henin withdrew from her doubles match Tuesday because of foot blisters.

Henin and partner Magui Serna were to play Maja Matevzic and Dragana Zaric in the third round, but Henin withdrew after beating Martinez.

Tuesday's other women's quarterfinals lacked the shifting fortunes and odd interludes that marked the Capriati-Williams match on a sunny, breezy day.

Twice, Capriati bounced her racket in frustration. In the second set, she pointed to her right hip during a break between games, then left the court with a trainer for treatment of a strained buttock.

After falling behind 4-0 in the third set, Williams also departed briefly.

"I was really nauseated," she said. "I just had to get out of there. I don't know how I came back."

She said she had a virus, felt weak from lack of food and nearly pulled out of her fourth-round match on Friday.

"I had no idea until she took the bathroom break," Capriati said. "I just asked the umpire. She just said that (Serena) had to use the bathroom. It was an emergency. I didn't want to know the details."

Capriati also received treatment during the match. She suffered a strained buttocks muscle.

Williams returned to win three of the next four games, but Capriati still led 5-3. Williams wouldn't get another point as Capriati won her 19th consecutive Grand Slam match.

Ahead 30-0, Capriati moved within a point of victory with a forehand chip that caught Williams too deep in the court to reach.

Serving for the match, Capriati faulted. But her second serve went to Williams' forehand and the return was long.

As the ball bounced inches away from Capriati, she looked straight down at it, raised her arms, lifted her head under her white cap and closed her eyes with a huge smile of relief.

Capriati was 14 when she became the youngest player to win a match at Wimbledon. Now, at 25, she continues her remarkable comeback from a shoplifting arrest, a stay in a drug rehab center and a long struggle to get in the best shape of her life.

Tuesday's match was her third quarterfinal this year against Williams. Capriati beat her at the Ericsson Open in Miami in March and the French Open in June.

This time, the fifth-seeded Williams came much closer to winning.

She led 5-3 in the second set and was ahead 0-30 on Capriati's serve. The fourth-seeded Capriati took the next four points but still had to break Williams' serve in the next game.

And she did it, winning the last point when Williams hit a forehand into the net.

"I just kept saying to myself, `Try to at least hold on to your serve and make her serve it out.' Then at 5-4 I just gave it everything I've got," Capriati said.

Capriati could have had an easier match if she hadn't faltered on some big points in the first set.

She led 5-4 and was serving for the first set. Before her next serve, one fan yelled, "Let's go, Jennifer." Another shouted, "Come on, Jen." Then she hit a backhand long.

Capriati had three other set points, lost them all, and dropped the 18-point game when she couldn't reach Williams' forehand passing shot.

The tiebreaker was 4-4, then Williams held serve. Capriati had the next two serves but lost both on forehand shots from the baseline to the net, giving Williams the set.

Capriati came back to win the first game of the second set at love. Then she faltered again. She wasted four break points, allowing Williams to hold her serve.

On the second break point, Capriati had a putaway volley but hit it long. Then she bounced the racket on the court in anger.

After Williams took a 3-2 lead, a trainer talked to both players. Capriati pointed to her right hip and left the court for about five minutes before play resumed. Both players then held serve.

Information from The Associated Press was used in this report.