Maria Sharapova struggled again in her Grand Slam tournament comeback at the French Open, needing three full sets and extra games to defeat 11th-seeded Nadia Petrova 6-2, 1-6, 8-6 and reach the third round.

PARIS — Maria Sharapova struggled again today in her Grand Slam tournament comeback at the French Open, needing three full sets and extra games to defeat 11th-seeded Nadia Petrova 6-2, 1-6, 8-6 and reach the third round.

Playing again with tape on her troublesome right shoulder, the unseeded Sharapova joined top-seeded Dinara Safina and defending champion Ana Ivanovic in the next round.

Sharapova, a three-time Grand Slam champion who has slipped to No. 102 in the rankings because of her injury layoff, won five straight games to close out the first set.

Trailing 4-2 in the deciding set, she broke Petrova to get back on serve at 4-4, and then saved two break points to take a 5-4 lead. She saved another break point while serving at 6-6.

Sharapova is making her first Grand Slam appearance in almost a year after missing the U.S. Open and the Australian Open because of her shoulder injury. She had surgery in October.

Safina easily beat 18-year-old Russian qualifier Vitalia Diatchenko 6-1, 6-1, and Ivanovic defeated Tamarine Tanasugarn of Thailand 6-1, 6-2.

Safina took a 5-0 lead to open the match, stretching her streak to 17 straight games after winning 6-0, 6-0 in the first round.

"Pretty good start for the tournament," said Safina, who lost in the Australian Open final and was the runner-up at Roland Garros last year. "I just played a good game today, good enough to win."

The 153rd-ranked Diatchenko didn't have many break opportunities against Safina.

"I felt so bad because I didn't play my best game today," Diatchenko said. "She's in good form. Every ball she put close to the line."

Ivanovic looked more comfortable on court after struggling in her opening match. The eighth-seeded Ivanovic broke the 32-year-old Tanasugarn twice in the first set and three times in the second.

"I just want to sort of get my way through the rounds and just feel more comfortable match after match," Ivanovic said. "Today I think I served some aces, which gave me some confidence in my serve, and that's something I've been working on."

The 21-year-old Serb finished with three aces.

No. 9 Victoria Azarenka of Belarus, No. 20 Dominika Cibulkova of Slovakia, No. 22 Carla Suarez Navarro of Spain, No. 25 Li Na of China, No. 27 Anastasia Pavlyuchenkova of Russia, No. 29 Agnes Szavay of Hungary and No. 32 Iveta Benesova of the Czech Republic also made it through, while No. 21 Alize Cornet of France reached the second round.

No. 15 Zheng Jie of China lost.

On the men's side, third-seeded Andy Murray defeated Potito Starace of Italy 6-3, 2-6, 7-5, 6-4. The Briton trailed 5-1 in the third set but broke Starace three straight times to win.

"On clay, there's always time for you to get sort of back into the match and find your game, even if you're struggling," Murray said.

Murray also reached the third round at Roland Garros last year but lost to Nicolas Almagro in four sets. In his only other appearance at the French Open, in 2006, he lost in the first round.

No. 7 Gilles Simon of France, No. 8 Fernando Verdasco of Spain, No. 12 Fernando Gonzalez of Chile, No. 13 Marin Cilic of Croatia, No. 17 Stanislas Wawrinka of Switzerland, No. 30 Victor Hanescu of Romania and No. 31 Almagro also advanced, but French veteran Fabrice Santoro played his last match at Roland Garros.

Santoro, who has made a record 67 Grand Slam appearances, lost in the first round of this year's French Open — his record-tying 20th — to Christophe Rochus of Belgium 6-3, 6-1, 3-6, 6-4.

"Twenty years. That counts for something in a lifetime," Santoro said. "It has been a long road, a fantastic career. I had a lot of fun and learned a lot."

Santoro and Rochus started their match Tuesday, but it was suspended by darkness with the Belgian leading 5-3 in the fourth set. The pair came back out onto the court after Safina's win and played only eight minutes.

"I'm saying to myself that the story is over, that a page is being turned," Santoro said. "I will no longer be on court next year. But I think that it is time to go."

No. 21 Dmitry Tursunov of Russia and No. 28 Feliciano Lopez of Spain also lost.

Later in the day, four-time defending champion Rafael Nadal and two-time Grand Slam champion Marat Safin were on court. No. 3 Venus Williams is also scheduled to play.