MADRID (AP) — Defending champion Roger Federer improved his clay-court game, defeating Benjamin Becker of Germany 6-2, 7-6 (4) Tuesday to reach the third round of the Madrid Masters.

The top-seeded Federer broke serve right away and again to close out the first set. He missed two match points when leading 6-5 in the second set before taking control of the tiebreaker.

Federer is seeking to regain his form on clay ahead of the French Open. He lost his first clay-court match of the year at the Rome Masters before exiting the Estoril Open at the semifinal stage.

"I'm happy with the way I reacted after all that happened in the last few weeks and months," Federer said. "The moment the match started, I felt great. I was hitting the ball fine, and I think the center court here just feels right to me."

The Swiss player captured the Madrid Masters title last year, before going on to win the French Open and Wimbledon. Federer will play either Stanislas Wawrinka or Julien Benneteau in the next round.

Fernando Verdasco lived up to his billing as home favorite by beating Ivo Karlovic of Croatia 7-6 (5), 6-3 in their first meeting on clay.

In a tight opening set, Verdasco struggled to handle Karlovic's serve although the sixth seed looked more comfortable in the second.

"The tiebreak in the first set boosted my confidence and allowed me to play more calmly in the second set, and in the end to break him," said Verdasco.

Wild-card entrant David Nalbandian, the champion in 2007, and opponent Tomas Berdych each withdrew because of injuries before their match. Organizers did not describe the injuries.

In the first round, 16th-seeded Thomaz Bellucci defeated Pere Riba of Spain 7-6 (5), 6-1.

Michael Russell and Mardy Fish, two players who narrowly failed to get through the qualifying phase, were drafted in as replacements. Fish won the match 6-2, 7-6 (1).

Juan Ignacio Chela, Eduardo Schwank, Philipp Petzschner Ernests Gulbis, Marcos Baghdatis, Stanislas Wawrinka, Victor Hanescu, John Isner, Mikhail Youzhny and Daniel Munoz-De La Nava also progressed to the second round.

On the women's side, 2009 finalist Caroline Wozniacki was beaten 6-2, 6-3 in an upset by 26th-ranked Alona Bondarenko. The Ukrainian will play Li Na of China in the third round.

Wozniacki said she was still recovering from an ankle injury although she was confident of being fully fit for the French Open.

"When you've twisted you're ankle a few times, as I have, you need your confidence back, especially on clay. It's uneven, and you need to be confident that you really can go out there and slide really wide," she said.

Alexandra Dulgheru of Romania beat sixth seeded Elena Dementieva of Russia, 6-1, 3-6, 7-5.

In other second-round matches, Patty Schnyder rallied past Agnieszka Radwanska 3-6, 6-4, 6-4, and Anabel Medina Garrigues defeated Marion Bartoli 6-2, 6-0.

Nadia Petrova stopped Anastasia Pavlyuchenkova 6-2, 7-5 in an all-Russian match, and Shahar Peer of Israel and Lucie Safarova of the Czech Republic also advanced. Andrea Petkovic stopped Flavia Pennetta 7-6 (3), 6-3 in her Madrid debut.