Roger Federer survived a tough match on his least favorite surface today, rallying from a 5-1 deficit in the third set to beat Jose Acasuso 7-6 (8), 5-7, 7-6 (2), 6-2 in the second round of the French Open.

PARIS — Roger Federer survived a tough match on his least favorite surface today, rallying from a 5-1 deficit in the third set to beat Jose Acasuso 7-6 (8), 5-7, 7-6 (2), 6-2 in the second round of the French Open.

Federer reached the last three finals at Roland Garros, but the clay-court major remains the only one of the four Grand Slam tournaments he hasn't won.

Against Acasuso, Federer was far from his best. But after losing seven straight games at the end of the second set and beginning of the third, the second-seeded Swiss reeled off five straight to force another tiebreaker.

"Of course, I'm thrilled to be through," said Federer, who saved four set points in the first tiebreaker. "It was sort of a fun match to be part of with so many ups and downs."

Venus Williams also came close to an early exit, needing to save a match point before defeating Lucie Safarova of the Czech Republic 6-7 (5), 6-2, 7-5. Fifth-seeded Jelena Jankovic joined the seven-time Grand Slam champion in the third round by defeating Magdalena Rybarikova of Slovakia 6-1, 6-2, and Serena Williams easily beat Virginia Ruano Pascual of Spain 6-2, 6-0.

Federer was in danger of ending his record 19 straight Grand Slam semifinal appearances, but the 13-time major champion won the third set and dominated the fourth.

"Mentally I've always been very strong, but I'm not being put in a position like this very often," Federer said. "So it was good to win both breakers."

The last time Federer lost before the semifinals was the 2004 French Open, when he fell in the third round.

Williams began her match Wednesday, but play was suspended because of darkness after the third-seeded American lost the first set. She faced a match point while trailing 5-4 in the final set but managed to hold serve, break Safarova and hold again for the win.

"Yesterday, I think I did too many things wrong. She just was firing for every shot and making them," Williams said. "Obviously, with the delay, was a lot of things to think about beforehand, what I could do different, and just tried to be as aggressive as I could.

"The last two sets, you know, it was close. But these kind of matches are really rewarding, and she was playing well. But I felt like I deserved it."

Jankovic had an easier time, moving a step closer to her third straight semifinal appearance at Roland Garros by beating Magdalena Rybarikova 6-1, 6-2.

"I think I'm coming back," said Jankovic, who started this season as the top-ranked player. "This is the most important thing for me, especially when you saw me playing a few months ago. It was really disastrous."

The fifth-seeded Jankovic won 15 of the first 17 points, and broke her opponent in the final game of the first set. In the second, she recovered from an early break to win four straight games, and closed out the match with her sixth break of service.

Jankovic lost in the semifinals at Roland Garros in each of the last two years. She made her first Grand Slam final at the 2008 U.S. Open.

"I'm trying to, little by little, play more aggressive and move into the net as much as I can, and, you know, try to improve my serve," Jankovic said.

Seventh-seeded Svetlana Kuznetsova of Russia also advanced, defeating Galina Voskoboeva of Kazakhstan 6-0, 6-2. No. 10 Caroline Wozniacki of Denmark and No. 24 Aleksandra Wozniak of Canada also won, but seeded French players Marion Bartoli and Alize Cornet lost along with No. 18 Anabel Medina Garrigues and No. 28 Sybille Bammer of Austria.

The 13th-seeded Bartoli, who reached the Wimbledon final in 2007, lost to Tathiana Garbin of Italy 6-3, 7-5, while No. 21 Cornet fell to Sorana Cristea of Romania 6-3, 6-2.

On the men's side, fifth-seeded Juan Martin del Potro defeated Viktor Troicki of Serbia 6-3, 7-5, 6-0. No. 10 Nikolay Davydenko of Russia and No. 16 Tommy Robredo of Spain also advanced.