Top-ranked Victoria Azarenka turned it on when she had to Monday, winning 12 of the final 14 games to reach the second round at the French Open.
The Australian Open champion, who took over the No. 1 ranking by winning in Melbourne, struggled for long stretches but came back to beat Alberta Brianti of Italy 6-7 (6), 6-4, 6-2.
"Sometimes I felt it was not my day. Sometimes I thought, `yeah, maybe I still fight. I still have a chance,"' Azarenka said. "Sometimes it was like, `you know what? Forget it. I don't want to do it."'
And although Azarenka rebounded over the final two sets, she finished the match with 60 unforced errors.
"I think it says it all. Bad days happen," Azarenka said. "Unfortunately today I had way more mistakes than I usually do, but, you know, it happens sometimes."
Defending women's champion Li Na also won easily, beating Sorana Cirstea of Romania 6-2, 6-1.
Last year, Li became the first Chinese player to win a Grand Slam singles title when she won at Roland Garros.
No. 3 Agnieszka Radwanska of Poland, No. 8 Marion Bartoli of France, No. 15 Dominika Cibulkova of Slovakia and No. 19 Jelena Jankovic of Serbia also advanced to the second round.
Azarenka was first up in the main stadium, and she didn't look good at the start. In the first set alone, she had 28 unforced errors.
"She started well ... but afterward she got a little bit tight. Things became a little bit more complicated for her," said former French great Amelie Mauresmo, who has been working with Azarenka. "She managed to turn the match around at the last minute by digging deep and finding the resolve to win."
The top-ranked Belarussian started the 2012 season with a 26-match winning streak. Her first loss came in the quarterfinals of the Sony Ericsson Open.
No top-seeded woman has ever lost in the first round at the French Open since the tournament began to allow foreign entrants in 1925.
In the other Grand Slam tournaments, it has happened four times, most recently when top-ranked and top-seeded Martina Hingis lost in the first round at Wimbledon in 2001.