Novak Djokovic saw off Britain's Andy Murray in a gripping late-night contest to reach the US Open semi-finals.

The world number one came through 7-6 (7-1) 6-7 (1-7) 6-2 6-4 in a match that lasted three hours and 32 minutes, and finished at 01:17 local time (06:17 BST).

Djokovic will play Japanese 10th seed Kei Nishikori in the last four on Friday.

Murray could take encouragement from his best performance since beating Djokovic to win Wimbledon last year, but the Serb proved relentless in their 21st meeting.

Defeat means that Murray has failed to get past the semi-finals of any tournament after undergoing back surgery in September 2013.

"I played well," said Murray. "Especially the first couple of sets was some good tennis.

"I played a poor tie-break in the first set definitely. I was down in the first set and I fought back. I was down in the second set and a break and I fought back.

"So I fought hard, I played some good tennis, but it wasn't enough."

The pair extended each other to the limit once again, and repeatedly had the 22,000 spectators in Arthur Ashe Stadium on their feet as brutal rallies were followed by roars of delight.

In a contest of numerous opportunities, it was the more clinical Djokovic who prevailed, winning seven of 10 break points while Murray converted just four of 16.

Murray created opportunities in Djokovic's first five service games as he came back from 4-1 down, with one thrilling 29-stroke rally bringing the crowd to life, but the Serb forced a tie-break and raced through it.

A double-fault saw Murray slip 2-0 behind and a stinging return at his toes made it 3-0 as Djokovic reeled off seven of eight points.

Murray was in deep trouble when he sent over a 68mph second serve and netted successive backhands and forehands to drop serve early in the second set, but the dire situation drew a positive reaction.

The heavy, flat forehand that is so often a marker of his form began to dominate, driving Djokovic deep into the corners.

After service breaks were again swapped, another tie-break was required, and this time Murray set about it with attacking intent.

A thumping forehand backed up by a sharp volley put the Scot in front and an increasingly fraught-looking Djokovic responded with a flurry of errors, allowing Murray to match his 7-1 scoreline from the opening set.

With two hours and 13 minutes on the clock, and midnight approaching, the fact Murray went into the match having spent three and a half hours longer on court than his opponent loomed large.

Just as battle appeared to have been joined, Murray handed back the initiative with a loose service game, floating a backhand over the baseline to fall behind.

Two chances to recover the deficit disappeared into the net and Djokovic, looking as sprightly as ever, confirmed his superiority with a second break to clinch the set.

Murray had never beaten Djokovic after losing the first set, and he now faced a mighty task to end that run, calling the trainer for a heat pack to apply to his back late in the fourth set.

The 2012 champion kept the Serb at bay, and his hopes of a second title alive, until he had to hold serve to stay in the match.

Djokovic earned two match points and Murray could only drag a backhand into the net, ending his US Open campaign at the quarter-final stage for the second year in a row.
(BBC)