Nadal gets walkover, Federer through

World number one Rafael Nadal was handed a walkover into the quarter-finals of the Madrid Open on Thursday when his third-round opponent Philipp Kohlschreiber was forced out of the claycourt event with a left leg injury.

Nadal was joined in the last eight by world number two Roger Federer, a 6-2, 6-4 winner over James Blake, and Andy Murray, who coped well with blustery conditions in the Magic Box stadium to dispatch Spanish 16th seed Tommy Robredo 7-5, 6-1.

Serbia's Novak Djokovic, chasing a fifth straight final appearance, also advanced with a routine 6-4, 6-4 victory over unseeded Italian Andreas Seppi.

Fans waiting to see local hero Nadal play Kohlschreiber on centre court were handed a disappointment around three hours before the match was due to begin when the ATP announced the German had withdrawn.

The Mallorca native is bidding for a sixth title of the season and a fourth on clay and will play seventh-seeded compatriot Fernando Verdasco for a place in the last four.

CRASHING RETURN

Federer fell to Blake at last year's Beijing Olympics and laid down a marker in the opening game against the American 14th seed, breaking serve with a crashing backhand return.

The 13-times Grand Slam winner, who has yet to win a title this year, wrapped up victory with a fifth ace on his first match point and will play Andy Roddick in the next round.

The sixth-seeded American was also given a walkover when his opponent Nikolay Davydenko withdrew with a left leg injury.

"I didn't really see it as a revenge match," Federer said of the Blake clash. "The tennis wasn't as good as in Beijing but I'm happy it was that easy. It was a solid performance."

A single break of the Robredo serve in the 11th game of a tight first set and three more in the second were enough to seal a comfortable win for world number three Murray and he converted his first match point with a backhand return down the line.

The Briton, who turns 22 on Friday, has never won a tour title on clay and is looking to improve his record on the surface ahead of the French Open which starts later this month.

He will next play Juan Martin Del Potro after the Argentine fifth seed battled past 11th-seeded Swiss Stanislas Wawrinka 4-6, 6-4, 6-4.

"It was tough from one end where the wind was blowing right into your face and Tommy was dictating a lot of points from that end in the first set," Murray told a news conference.

"I was just a little bit tense when I had my chances. I had a lot in the first set and didn't take them and played a little too passive.

"The second set was much better and I started to dictate a lot of the points."

World number four Djokovic had a reasonably smooth passage against Seppi to set up a last-eight clash against wildcard Ivan Ljubicic, who battled back from a set down to beat eighth seed Gilles Simon 3-6, 6-4, 6-3.

"I wish I'd had a withdrawal," Djokovic said at a news conference. "As it was I had to work very hard."