PARIS (AP) -- Victoria Azarenka was back to her top-ranked self at the French Open on Wednesday.
The Australian Open champion from Belarus easily advanced to the third round at Roland Garros by beating Dinah Pfizenmaier of Germany 6-1, 6-1 on Court Philippe Chatrier.
In the first round, Azarenka struggled early before winning 12 of the final 14 games to advance. She committed 60 unforced errors in that opening match, but brought that number down to only 11 on Wednesday.
Azarenka reached the quarterfinals at Roland Garros last year, matching her best performance at the clay-court Grand Slam.
U.S. Open champion Sam Stosur also advanced, beating Irina Falconi of the United States 6-1, 6-4.
Later Wednesday, top-ranked Novak Djokovic was playing Blaz Kavcic of Slovenia, and 2009 champion Roger Federer was scheduled to face Adrian Ungur of Romania. In the women's tournament, No. 3 Agnieszka Radwanska of Poland was to play Venus Williams in the last match on Chatrier.
On Tuesday, Serena Williams showed that, even after 13 Grand Slam championships and dozens of other titles, she is capable of throwing away a big lead.
Williams led 5-1 in the second-set tiebreaker and was two points from victory nine times but still lost to Virginie Razzano of France 4-6, 7-6 (5), 6-3 - the first time she has ever lost in the first round of a Grand Slam tournament.
"I definitely was nervous. I'm always a little nervous in every match I play, which I think is a little bit healthy," said the fifth-seeded Williams, who had been 46-0 in the first round of majors. "I was definitely a little nervous."
Williams entered the tournament with a 17-0 record on clay this year. And it looked like No. 18 was in the bag late in the second set.
But Razzano won six straight points to take the set and then won five straight games in the third.
"I just felt I couldn't get a ball in play," Williams said. "You know, when I did, I just felt like I was hitting late and, I mean, how can you hit late on a clay court? It was kind of odd."
Defending men's champion Rafael Nadal had no such trouble, starting his quest for a record seventh French Open title by beating Simone Bolelli of Italy 6-2, 6-2, 6-1. Maria Sharapova had an even easier time, scoring a "double bagel" in her 6-0, 6-0 win over Alexandra Cadantu of Romania.
"I feel like with every year I have improved," Sharapova said, "and I enjoy it much more."