US Open: Walkover for Novak Djokovic as toiling Wawrinka retires

The pair had begun their fourth-round clash on Tuesday night before rain brought a premature end to play and they were on and off the court again before the match finally resumed just after 1pm local time on yesterday. Djokovic was tested in the first set, but after that it was a one-sided contest and Wawrinka called it a day with the second seed leading 6-4, 6-1, 3-1, although the reason was not immediately apparent.

They managed only two games before the rain came on Tuesday, Djokovic winning both of them, but Wawrinka quickly retrieved the break on the  resumption.

The last time the Swiss beat Djokovic was six years ago and his cause was not helped when he promptly dropped his serve again. Djokovic has cruised through the draw in New York, but he was making more unforced errors than usual on a sparsely populated Louis Armstrong Stadium and was unable to serve out the set.

However, for the second time, Wawrinka failed to hold serve straight after breaking and things swiftly went downhill in the second set for the 18th seed.

After saving a break point in the opening game, Djokovic reeled off four games in a row, and Wawrinka responded by smashing his racquet on the court. It did not help, though, and he was quickly a break down in the third set. Wawrinka talked to the trainer after the change of ends and, following the fourth game, he called Djokovic to the net and shook hands.

Serbia’s Janko Tipsarevic successfully wore down Germany’s Philipp Kohlschreiber to win their rain-delayed fourth-round clash 6-3, 7-6, 6-2.

Kohlschreiber blasted 12 aces during the two-and-a-half-hour clash that began on Tuesday but was suspended for a day because of rain. Tipsarevic kept his cool in the tricky, windy conditions and eventually overcame his weary opponent, whose previous two matches had gone five sets.

Tipsarevic, seeded eighth, is through to the quarter-finals at Flushing Meadows for the second consecutive year, but has never made a semi-final at any Grand Slam.

His next opponent is Spanish fourth seed David Ferrer, who beat the foul weather to win his fourth round match on Tuesday and get a day off. “I’m extremely happy how I managed to play good on key and important moments in all three sets,” Tipsarevic said. “I think this was the main difference. All three sets were, even though the score doesn’t show it, really, really tight.

“But in important moments I guess because of the confidence I have and the way that I have being playing in the last couple months showed that I make the right decisions in the right moments of the match.”

On facing Ferrer, he added: “It’s going to be a really, really difficult battle, because both of us are groundstroke players and we play well from the back. We don’t have huge, huge weapons, so I think a guy who is tactically better and mentally stronger is going to be the winner.”