Rafael Nadal returns a shot during his 2nd round match against Ryan Sweeting of the United States at the 2011 Wimbledon tennis championships in London, Britain, June 22, 2011. Rafael Nadal won 6-3, 6-2, 6-4. (Xinhua/Zeng Yi)

Top seed Rafael Nadal powered through Wimbledon debutant Ryan Sweeting of the United States Wednesday in three straight sets, setting up a third round match against Luxembourg's Gilles Muller.

The defending champion eased into the Wimbledon last 32 through a victory of 6-3, 6-2, 6-4. The world number one, bidding for a third Wimbledon title and 11th career Grand Slam crown, is expected to go through a tough match next round on to tackle Muller, the only man other than Roger Federer to beat Nadal at the All England Club since 2005.

"It was a long time (ago), but he beat me," said Nadal, the Wimbledon champion in 2008 and 2010. "Gilles is a very dangerous player. He has a very good serve, good volley. He's especially very dangerous player in this kind of surface. So will be tough match for me."

Muller made it through when Canadian 31st seed Milos Raonic retired after just five games of their second round clash when he fell awkwardly and injured his leg.

Nadal said he preferred to play without the #80 million roof covering the action on Centre Court.