• US Open

Andy Murray through to US Open quarter-finals

Andy Murray continued his defence of the US Open title with a hard-earned four-set victory © AP

Enlarge

Andy Murray beat Uzbekistan's Denis Istomin 6-7 (5-7) 6-1 6-4 6-4 to set up a US Open quarter-final against Stanislas Wawrinka.

It was not Murray's best performance as he allowed himself to be upset by several bad line calls and the persistent wind, but despite dropping the first set he was never really stretched.

"I wanted to just try and get through the match," said Murray. "In the end it was difficult conditions. It was extremely windy.

"With the way he plays, he hits the ball pretty big and flat on both sides, strokes pretty low, hard at times to control. He made it very difficult for me.

"With the way the third set ended up going, I was just very happy to get it done because he had chances at the end of the third set to go ahead."

Murray had led the first-set tiebreak 5-3 but then endured a poor spell that included three errors and a wonderful forehand winner from Istomin, the set ending on a wild Murray forehand.

The defending champion reasserted himself in style though, winning nine of the next 11 games to take the second set comfortably and move 3-1 ahead in the third. However, an umpire overrule irritated Murray - "I'm having to replay that point, are you kidding me?" he said - and Istomin broke to level the set at 3-3.

Again Murray refocused, forcing four break points against the world number 65 before finally converting and seeing out the remainder of the set with the break in hand.

The decisive moment of the fourth set came at 4-4, when the Scot broke on an Istomin error, before serving out to complete the victory.

"I think hopefully I'll start playing a little bit better from now on," added Murray.

"Sometimes the first week of a Slam I've played very well, sometimes you maybe feel like there's a little bit of something to lose. I don't know.

"But I'm in the quarter-finals of a Slam. It's not an easy thing to do, and the matches are going to get tougher. I'll have to up my game."

He will meet ninth-seeded Wawrinka in the last eight after the Swiss upset fifth seed Tomas Berdych 3-6 6-1 7-6 (8-6) 6-2 on Louis Armstrong Stadium.

The third set proved pivotal, extending to 70 minutes after Wawrinka twice failed to serve it out then had to rally from 4-1 down in the tiebreak before winning it with an ace.

Wawrinka triumphed in his only previous meeting with Murray at the US Open in the third round three years ago, and the two men practise together often.

"He's improved I think this year quite a bit," Murray said of Wawrinka. "He has fewer weaknesses. He's more experienced now. He has a very good backhand, he serves well. he's solid up at the net, he makes a lot of returns.

"He makes it very tricky for you. He's a top player. It will be a very tough match for me."

Download ESPN's new UK sport app, a fresh and powerful new way to follow your favourite UK sports news, scores and video.

© ESPN Sports Media Ltd