PARIS - Novak Djokovic extended his perfect season into the French Open, beating Thiemo de Bakker yesterday in the first round, 6-2, 6-1, 6-3.

The second-seeded Serb improved his 2011 record to 38-0 - and stretched his winning streak to 40 - on the second day of the tournament at Roland Garros. And he barely had to sweat doing it, breaking his Dutch opponent six times.

"I was serving really, really well and being very aggressive, using every opportunity to step into the court," Djokovic said. "I was quite in control of the match."

Roger Federer, meanwhile, joined Djokovic in the second round by beating Feliciano Lopez, 6-3, 6-4, 7-6 (3), but sixth-seeded Tomas Berdych was knocked out by French journeyman Stephane Robert in five sets.

On the women's side, top-ranked Caroline Wozniacki eliminated 40-year-old Kimiko Date-Krumm, 6-0, 6-2, and defending champion Francesca Schiavone beat Melanie Oudin, of the United States, 6-2, 6-0.

Schiavone, who last year became the first Italian woman to win a Grand Slam singles title, won four straight games in the first set after being broken early by her 19-year-old American opponent. The fifth-seeded Schiavone then won seven straight games.

Djokovic walked out onto center court as the co-favorite after beating Rafael Nadal in two clay-court finals leading up to the French Open. He could only meet Nadal in the final at Roland Garros, and if he does he will be assured of taking over the No. 1 ranking from the Spaniard regardless of that result.

"Pressure is always there," said Djokovic, who turned 24 on Sunday. "I know there is a lot of expectations because of the streak I have, but, look, I'm really happy the way I'm handling things right now on and off the court."

Djokovic needs five more wins to break John McEnroe's Open-era record of 42 for the best unbeaten start, and a sixth victory will make him the first man to win the Australian and French Opens back-to-back since Jim Courier in 1992.

"Coming into a Grand Slam with three titles on clay courts and winning against the best player ever on this surface gives me a lot of motivation, a lot of confidence that I'm trying to use on the court," Djokovic said.

Nadal, who is looking for his sixth French Open title, doesn't get on court until today, but Federer progressed without facing a single break point against his Spanish opponent.

"Important thing from my side was to be solid in my own serve," Federer said, "which I was all the way through from start to finish."

The third-seeded Federer, who completed a career Grand Slam at Roland Garros 2 years ago, lost in the quarterfinals last year to end a streak of 23 straight major semifinal appearances.

Berdych, who last year reached the semifinals at the French Open and the final at Wimbledon, was knocked out by the 140th-ranked Robert, 3-6, 3-6, 6-2, 6-2, 9-7.

"Maybe it's too early to analyze how was that or what was happening on the court," Berdych said "That's what can happen in the long matches, and . . . sadly it happened to me today."

Berdych held a match point while leading 5-4 in the fifth set, but Robert saved it and went on to earn only his second win at a Grand Slam tournament.

Wozniacki, unbothered by her bandaged left thigh, dominated from the start and won the first seven games until Date-Krumm finally held serve. Date-Krumm made her debut at Roland Garros in 1989, a year before Wozniacki was born. She retired in 1996 and made her return 12 years later.