Kuerten improved to 3-2 all-time against the Russian, winning three of four matches on clay. The Brazilian also beat Kafelnikov in the quarterfinals here in 1997 en route to his first career title.

The fourth seed on the women's side also was defeated today as No. 8 Arantxa Sanchez-Vicario of Spain advanced to her 10th French Open semifinal with a 6-0, 1-6, 6-2 victory over Venus Williams of the United States, one of three American women to lose in the quarterfinals today.

Top seed Martina Hingis of Switzerland had no trouble, coasting a 6-1, 6-3 to victory over American Chanda Rubin.

A runner-up here in 1997 and 1999, Hingis will face No. 6 Mary Pierce of France, a finalist in 1994, in the semifinals. With a vocal crowd behind her chanting "Mary, Mary", Pierce defeated third seed and three-time winner Monica Seles of the United States, 6-4, 3-6, 6-4 today. Pierce was a finalist here in 1994.

A visibly tired Kafelnikov played 24 of a possible 25 sets in his five matches here and logged more than 15 hours on court, including three hours today. He overcame a whopping 112 unforced errors and a 2-5 deficit in the fifth set to outlast Fernando Vicente of Spain in the fourth round on Sunday.

Kafelnikov was in position to close out Kuerten with a 4-2, 40-15 lead in the fourth set, but he lost his serve and dropped 10 of the last 12 games.

"I had the match in hand," Kafelnikov said. "I just gave it away. Up until 4-2 in the fourth set, Gustavo was nowhere to be seen. I was in total control of the match."

The 26-year-old Kafelnikov, who has not won a claycourt event since taking both the singles and doubles crown here in 1996, came into this event having lost 10 of 15 matches on the dirt. He fell to 2-5 in five-set matches at the French Open, with both losses coming to Kuerten.

The 23-year-old Kuerten has had an easier time by far, posting straight-set wins in three of his first four matches, and is considered one of the favorites to win this tournament, though he realizes he is fortunate to still be alive.

"I think after this, I could be in Brazil already," he said. "I think that everyone could see that I was having tough moments there. He was playing better, ready to win. I can not explain why things turned around, but it just did."

Kuerten was runner-up at the Tennis Masters Series tournament in Rome before winning the elite event in Hamburg. Kuerten also claimed the Chevrolet Cup at Santiago, Chile and all seven of his career titles have come on clay.

In a battle of Spaniards, 20-year-old Juan Carlos Ferrero, the 16th seed, upset 1998 finalist Alex Corretja, the 10th seed, 6-4, 6-4, 6-2, in today's only other quarterfinal.

Hingis, vying for her first title at Roland Garros, needed just 57 minutes to defeat Rubin.

"I felt very good physically out there," Hingis said. "I knew I had to against Chanda because she came out firing, too. She came to the net a lot -- before I was able to pass her and do things."

Hingis has had trouble winning over the crowd at Roland-Garros after an incident in last year's final with Steffi Graf and will not have the fans on her side against Pierce.

"Every match is going to be tough from now on," she said. "Either the crowd is with or against you. I think the most important thing is you're happy and confident with yourself. You shouldn't let anybody get too many opportunities, just play your game."

Pierce, who became the first Frenchwomen to win a Grand Slam event in the Open era in 1995 when she captured the Australian Open, has made a surprising run here after winning only one match in her previous two tournaments.

"The crowd support was awesome," Pierce said. "I'll take it as it comes. I love the crowd and want their support, but if there comes a time when it turns around, I won't let it affect me."

Sanchez-Vicario, who improved to 71-11 at Roland Garros, snapped a four-match losing streak against Williams to raise her record against the American to 3-4 and reach her 10th French Open semifinal. In the semifinals, she will play a fellow Spaniard in Conchita Martinez, a 7-6 (7-5) 6-1 winner over Spanish qualifier Marta Marrero.

A three-time winner here, Sanchez-Vicario broke Williams six times in 10 break-point chances. The 28-year-old took advantage of six double faults and 52 unforced errors by Williams, who was playing in just her third event of the season due to tendinitis in both wrists.

The 19-year-old Williams won just 56 percent of her first-service points and only 36 percent on her second serve. She chalked today's loss to a lack of match practice.

"I think so because each shot I have to think about," Williams said. "Under any normal conditions, I don't have to think about my shots. It's like every shot, especially on the serve. I thought she played very well. What can I say? I think the score tells the story of the whole match."

Two men's fourth-round matches held over from Monday due to darkness were closed out today, both in upsets.

Albert Costa of Spain ousted ninth seed Lleyton Hewitt of Australia, 6-3, 4-6, 6-2, 6-4, and Franco Squillari of Argentina bounced 15th seed Younes El Aynaoui of Morroco, 6-4, 6-1, 6-3.

Costa delivered 35 winners in the three-hour marathon, joining Corretja and Ferrero as fellow Spaniards who made it to the quarterfinals. He also reached the Round of Eight here in 1995.

Hewitt could not overcome a sloppy performamce, committing 73 unforced errors, including 11 double faults. He also converted just three of nine break points.

Martina Navratilova's third-round women's doubles match today was suspended in the second set due to darkness.

The 43-year-old Navratilova, who is playing in her first French Open since 1994, is teamming with Mariaan de Swardt. They have a 6-2, 1-3 lead over the sixth-seeded French duo of Alexandra Fusai and Nathalie Tauziat.

Navratilova and de Swardt defeated the 12th-seeded Slovenian duo of Tina Krizan and Katarina Srebotnik, 7-6 (7-2), 7-5, on Saturday to reach the third round.

A two-time singles champion and seven-time doubles winner at the French Open, Navratilova is playing doubles in four tournaments as part of her comeback, although she has stated that she is playing for fun rather than winning titles.

After playing in Paris, Navratilova will compete at a grasscourt event in Eastbourne, England before attempting to tie Billie Jean King for the most overall Wimbledon titles with 20 later this month.

Navratilova was eliminated in the second round of mixed doubles on Sunday.