US Open 2011: Federer beats Tsonga to set up Djokovic semi

Federer was a late-night winner for the second match in a row

Five-time champion Roger Federer dismissed Jo-Wilfried Tsonga in straight sets to earn himself a US Open semi-final against Novak Djokovic.

Federer made amends for successive defeats by Tsonga that included June's Wimbledon quarter-final as he won 6-4 6-3 6-3 in the night match.

World number one Djokovic earlier came through a tough encounter with fellow Serbian Janko Tipsarevic.

Rafael Nadal made the last eight in the delayed bottom half of the draw.

Federer coped with yet another rain interruption in the final match of the day, despite dropping serve on the resumption at 3-2, and found Tsonga in less sparkling form than at Wimbledon or in Montreal last month.

The blistering winners of previous matches were few and far between from the Frenchman and Federer kept him under control with some solid serving to win in one hour and 53 minutes.

Federer now faces a rematch of last year's semi-final against Djokovic, which the Serbian won in five dramatic sets.

"I played great," said Federer. "For me it continues, and that is awesome. I'm very happy with the way I'm playing, the way I'm moving and I'm enjoying myself on the court."

Defending champion Nadal beat Gilles Muller in their delayed fourth-round match during the afternoon session and will face Andy Roddick in the last eight.

Nadal had led the protests at the slippery courts on Wednesday as players managed only 15 minutes of action before rain stopped play, but when he resumed on Thursday trailing the big-serving Muller 3-0 he was fully focused as he powered to a 7-6 (7-1) 6-1 6-2 victory.

The Spaniard's form suggested he is getting back to somewhere near his best but his attention quickly turned to the scheduling issues that have dogged this US Open.

"That's not fair, but that's what it is," said the world number two. "Here in the Grand Slams, if I am in the position of the US Open or Wimbledon or Australia, Roland Garros, I will do the same. Why not?"

The tournament would later announce that the men's final will be rescheduled from Sunday to Monday, giving the finalists a day off after the semi-finals.

Roddick, the 2003 champion, must beat Nadal if he is to make it that far and he enjoyed a superb 6-3 6-4 3-6 6-3 win over fifth seed David Ferrer on Court 13, after their match was moved when water began seeping through near the baseline on Louis Armstrong Stadium.

"I enjoyed it," said the 29-year-old American. "I like playing kind of the smaller, more intimate stuff when I can. It was a little bit of everything."

Djokovic was below par for much of his quarter-final, allowing Tipsarevic back from 5-2 down to serve for the first set only to take it in a tie-break.

The top seed broke his opponent's resistance in the third set before there was another alarm in the fourth when he needed treatment to a toe injury.

But in the end it was Tipsarevic who called it quits at 7-6 (7-2) 6-7 (3-7) 6-0 3-0 down after earlier receiving treatment to his leg.

"My left toe is bleeding," said Djokovic afterwards. "These things happen all the time when you're sliding like I do."

On a packed day at Flushing Meadows as organisers looked to get the schedule back on track, fourth seed Andy Murray beat Donald Young 6-2 6-3 6-3 and will next face American John Isner, who defeated Gilles Simon 7-6 (7-2) 3-6 7-6 (7-2) 7-6 (7-4).