PARIS (AP) - 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.''
Brianti, a 32-year-old veteran with one career WTA title, won the first set and then led 4-0 in the second before losing six straight games.
Azarenka had 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.''
Novak Djokovic and Roger Federer managed less stressful victories.
Federer beat Tobias Kamke of Germany 6-2, 7-5, 6-3. The 16-time major champion equaled Jimmy Connors' record of 233 Grand Slam match wins in the Open era. Federer is 233-35 at tennis' top four tournaments. Connors was 233-49.
"That's a big one, because that was longevity,'' Federer said. "Jimmy is obviously one of the greats of all time and was around for 20 years.''
The top-ranked Djokovic, who is trying to win his fourth straight Grand Slam title, never faced a break point in beating Potito Starace of Italy 7-6 (3), 6-3, 6-1.
"It's just the first match here,'' Djokovic said in French on court after the match. "It's still a very long way to go before we talk about the final.''
Defending champion Li Na won her opening match at the French Open, beating Sorana Cirstea of Romania 6-2, 6-1 on Monday.
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.
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.
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.
For Venus Williams, just playing at this year's French Open was an accomplishment. Winning was a bonus.
Williams played at a major tournament for the first time since last August, when she withdrew before her second-round match at the U.S. Open. It was then that she revealed that she had been diagnosed with Sjogren's syndrome, a condition that can cause fatigue and joint pain.
It didn't slow her down in the last two sets Sunday. The seven-time Grand Slam champion recovered from a poor start and beat 19-year-old Paula Ormaechea of Argentina 4-6, 6-1, 6-3 to reach the second round.
"I just learned how to live with this. It's different,'' Williams said. "I have a lot to learn still. ... I learn a lot every week, especially having to play a professional sport. So that's a challenge, just learning to live.''
Williams was one of six major champions who advanced on the opening day of the clay-court tournament. The only one that lost was Andy Roddick, the 2003 U.S. Open winner.
Another American woman won her first round match. Qualifier Lauren Davis, an 18-year-old from Boca Raton, Fla., knocked off 30th-seeded Mona Barthel of Germany 6-1, 6-1 in the first round of the French Open on Monday.
It was Davis' 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.
Two-time Grand Slam finalist Vera Zvonareva of Russia withdrew from the tournament shortly before her first-round match Monday, citing an injured right shoulder.
The 11th-seeded Zvonareva was replaced in the draw by Sesil Karatantcheva of Kazakhstan, who lost in qualifying. 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.
Zvonareva was the runner-up at Wimbledon and the U.S. Open in 2010.
In men's action, Feliciano Lopez of Spain quit because of a side muscle injury Monday after losing the first five games of his first-round match against Florent Serra of France.
The 15th-seeded Lopez pulled the muscle while practicing at Roland Garros on Thursday.
"In the beginning, I felt it was nothing really serious, but (the) day after, I couldn't play almost,'' Lopez said. "I tried to rest during the weekend just to try to play today, but it was impossible.''
He said he hopes to be healthy in time for Wimbledon, which starts June 25.