MONACO — Rafael Nadal beat Juan Ignacio Chela 6-2, 6-3 Wednesday in the second round of the Monte Carlo Masters, a first step in his bid for a fifth straight title in this clay-court tuneup for the French Open.

Each time Nadal has won Monte Carlo he has gone on to capture the French. The top-ranked Spaniard has won 17 straight matches on clay since losing to Juan Carlos Ferrero in the second round of the Rome Masters in May 2008.

Nadal will next Nicolas Lapentti, who downed two-time Grand Slam champion Marat Safin of Russia 7-6 (6), 2-6, 7-6 (6).

"I had some tough moments during the match," said Nadal, who has won 23 straight matches at Monte Carlo. "I played some games well; I had some terrible games. ... I have to improve my concentration in the next match."

Roger Federer, who lost to Nadal in the last three Monte Carlo finals, defeated Andreas Seppi of Italy 6-4, 6-4 to reach the third round. Federer, ranked No. 2, will face 13th-seeded Stanislas Wawrinka, his doubles partner at the Beijing Olympics, on Thursday. Wawrinka beat Martin Vassallo Arguello of Argentina 2-6, 7-5, 6-2.

Federer played his first match since marrying longtime girlfriend Mirka Vavrinec on Saturday in his hometown of Basel, Switzerland. He can equal Pete Sampras' record of 14 major titles if wins the French Open for the first time.

Federer began clay-court preparations 10 days ago, and Seppi was an ideal first test.

"I knew there was going to be some long rallies with Seppi. He's very steady off both sides," Federer said. "So on a good day he can be really dangerous. I've already played him twice this year, which was kind of good going into this match, knowing what to expect."

The biggest adjustment, Federer said, is getting used to the unpredictable bounces on clay.

"We've been playing on hard court now for nine months ... you never see a bad bounce," Federer said. "So all of a sudden you're a little bit worried, sometimes hitting half volleys because they can bounce onto your frame."

Federer has beaten Seppi three times this year and improved to 5-0 overall without dropping a set against the big-serving Italian.

Fifth-seeded Juan Martin Del Potro of Argentina became the highest seeded player to be eliminated when he failed to capitalize on a good start and lost to wild card Ivan Ljubicic 4-6, 6-1, 6-4.

Also advancing were No. 7 Fernando Verdasco of Spain, No. 8 Nikolay Davydenko of Russia, No. 12 David Nalbandian of Argentina and Simone Bolelli of Italy.

Verdasco beat Philipp Kohlschreiber of Germany 6-3, 6-4; Daydenko defeated Ivo Karlovic of Croatia 6-4, 6-3; Nalbandian downed Marcel Granollers of Spain 4-6, 6-3, 6-1; and Bolelli ousted Janko Tipsarevic of Serbia 7-5, 6-3.