PARIS -- Top-ranked Victoria Azarenka survived a scare in the first round of the French Open.
Azarenka, the reigning Australian Open champion who took over the No. 1 ranking by winning in Melbourne, 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."
The Russian Zvonareva withdrew shortly before her first-round match, citing an injured right shoulder. The 11th seed was replaced in the draw by Sesil Karatantcheva of Kazakhstan, who lost in qualifying.
Barthel of Germany fell to American qualifier Lauren Davis, an 18-year-old from Boca Raton, Fla.
Azarenka won 12 of her last 14 games but struggled with her game throughout, committing 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."
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 Martina Hingis lost in the first round at Wimbledon in 2001.
Brianti, a 32-year-old veteran who has won one WTA title in her career, won the first set and then led 4-0 in the second before losing six straight games.
Azarenka started the 2012 season with a 26-match winning streak. Her first loss came in the quarterfinals of the Sony Ericsson Open.
She is now 36-3 this year.
Davis won 6-1, 6-1, her first victory in three career Grand Slam matches. She played cleanly, making only 11 unforced errors. Barthel made 44, including 12 double-faults.
The 5-foot-2 Davis finished last season ranked 319th, and she entered this week 162nd.
The seventh-seeded Li became the first Chinese player to win a Grand Slam singles title when she won at Roland Garros last year. She also reached the Australian Open final in 2011 but lost to Kim Clijsters.
Cirstea is ranked 43rd. She reached the quarterfinals at the French in 2009.
The injured Zvonareva was the runner-up at Wimbledon and the U.S. Open in 2010. Karatantcheva was to face Zvonareva's opponent, Timea Babos of Hungary.
Karatantcheva was a quarterfinalist at age 15 at Roland Garros in 2005, when she upset Venus Williams in the third round.
Information from The Associated Press was used in this report.