Mauresmo, who won Wimbledon and the Australian Open in 2006, also lost to Safarova while trying to defend her title at Melbourne in January.

"The fact is that there's no miracle today," Mauresmo said. "I mean, I've been struggling for weeks now. Coming here at the French Open, I didn't really know what to expect."

The Frenchwoman has never reached the semifinals at Roland Garros in 13 attempts since her debut in 1995. She said she's still not fit after having her appendix removed in March.

Maria Sharapova reached the fourth round of the French Open for the fourth time. She rallied from 4-1 down in the second set to beat Alla Kudryavtseva 6-1, 6-4 despite a bothersome right shoulder.

Two-time defending champion Rafael Nadal defeated Albert Montanes 6-1, 6-3, 6-2 in his third-round match.

Mauresmo led 3-0 in each set. But she double-faulted for the eighth time to fall behind 2-0 in the tiebreaker, and a long backhand gave Safarova three match points. Safarova won when Mauresmo returned her serve into the net.

"I was fighting for each point," said Safarova, a Czech seeded 25th. "I never give up."

At 4-3 in the first set, the tournament doctor came on center court to treat Mauresmo, who then left for several minutes to take a medical break. When she returned, the top of her right thigh was wrapped.

"I did not have any particular goal for this tournament because I didn't have enough preparation," Mauresmo said. "You want to give your best in each match, to go to the end. But it was not enough for me today."

Mauresmo reached the quarterfinals in 2003 and 2004 and lost in the fourth round last year. Safarova lost in the first round at Roland Garros in 2005 and 2006.

"I was very nervous at the beginning," Safarova said. "I tried to just concentrate on each point. I tried to come for each point, to play aggressive. I think that's why I won."

She will next play Anna Chakvetadze. The ninth-seeded Russian beat No. 21 Ai Sugiyama of Japan 6-4, 6-4.

Sharapova, who lost in the fourth round last year and reached the quarterfinals at Roland Garros in 2004 and 2005, next faces No. 14 Patty Schnyder.

Schnyder beat Karin Knapp of Italy 6-1, 4-6, 7-5; No. 15 Shahar Peer of Israel defeated No. 17 Katarina Srebotnik of Slovenia 6-1, 4-6, 6-3; and No. 24 Anabel Medina Garrigues of Spain topped No. 12 Daniela Hantuchova of Slovakia 4-6, 7-6 (2), 7-5.

Nadal, who is 17-0 at Roland Garros, saved nine break points against Montanes, who was trying to reach the fourth round at a Grand Slam for the first time.

No. 16 Marcos Baghdatis of Cyprus was leading 6-2, 6-2 when Jan Hajek of the Czech Republic retired with an injured right shoulder, and No. 6 Novak Djokovic rallied to oust Olivier Patience of France 7-6 (2), 2-6, 3-6, 7-6 (4), 6-3.

Also, Jonas Bjorkman topped Oscar Hernandez 6-7 (3), 6-3, 6-0, 6-1; Igor Andreev beat Paul-Henri Mathieu 7-6 (4), 6-0, 6-3; and Carlos Moya defeated Juan Pablo Brzezicki 6-1, 6-3, 7-5.