PARIS -- To defend her French Open title, Jennifer Capriati will need to beat at least one Williams sister. And perhaps both.

	Jennifer Capriati will likely have to beat both Williams sisters back-to-back to defend her title.

With "Friends'' star Matthew Perry pulling for her from the guest seats, Capriati beat Jelena Dokic 6-4, 4-6, 6-1 Tuesday to set up a semifinal showdown against Serena Williams.

"I'm going in there thinking that she's really the one to beat now. She's on top of her game,'' Capriati said.

Williams overpowered Mary Pierce 6-1, 6-1, right after Venus Williams beat Monica Seles 6-4, 6-3, earning each sister her first trip to the French Open semifinals.

Venus Williams next faces unseeded Clarisa Fernandez, who defeated fellow Argentine Paola Suarez 2-6, 7-6 (5), 6-1 in Tuesday's first quarterfinal.

Top-seeded Capriati has lost all three of her matches against Serena Williams this year -- in finals at Scottsdale and Miami and in the semifinals at Rome last month on clay.

Serena has captured the past four matches, but Capriati won both Grand Slam meetings with three-set victories in the quarters last year at both Roland Garros and Wimbledon.

"We've played many times. She's beaten me the last few, but we haven't played in a Grand Slam in a while,'' Capriati said. "Sometimes she gets nervous in the Grand Slams or maybe she doesn't play as well. Or I play better.''

After losing her serve to drop the second set against Dokic, Capriati needed just 19 minutes to win the third, capturing the final five games. Dokic had four of her 14 double faults in the last set, including on match point.

"In the second set, I was starting to struggle. I had to concentrate and focus in the third. I had to watch the ball more than usual because it was very dark,'' Capriati said of the late-ending match.

Serena Williams simply overwhelmed Pierce, the 2000 French Open champion, giving up just two points over her final five service games and winning in just 49 minutes.

Venus Williams, a two-time Wimbledon and U.S. Open winner, showed that her fast-paced game can work on the clay, as well. Her quickest serve during the match was clocked at 118 mph.

"I can play on anything. I do know how to slide and I enjoy stepping into the ball,'' she said. "I don't think (Seles) played her best.''

No. 6-seeded Seles, a three-time French Open champion, made 36 unforced errors against Venus in the 1-hour, 13-minute match that was interrupted 48 minutes by rain in the first set.

"The ball just comes so fast you have to be on it every moment,'' Seles said. "And when she serves and when she is going for it, obviously it's very fast. And she didn't make as many errors.''

Venus, who lost to Seles for the first time in seven previous meetings in the Australian Open quarterfinals, led 3-1 when the rain came. Once play resumed, Seles broke for 3-4 and held to even the match.

But Venus, with the aid of Seles' double fault, broke to win the first set. She hit an ace for a 3-2 lead in the second and broke again as Seles double faulted.

Fernandez became the first unseeded semifinalist at the French Open since Capriati in 1990. The 5-foot-11 left-hander upset No. 4 Kim Clijsters in the third round and No. 13 Elena Dementieva in the fourth. Suarez was hurt by eight double faults and lost her serve all four times in the final set.

Their friendship was evident when Fernandez's ace to win a second-set tiebreaker was called out but Suarez conceded it was good and walked off the court.