US Open 2014: Andy Murray suffers four-set defeat to Djokovic in quarter-finals

Murray had spent three and a half hours longer on court in his first four matches but the form he showed in beating Jo-Wilfried Tsonga two days before had fuelled cautious optimism.

The New York crowd settled in for a long night as Djokovic began the contest at 9.43pm with a second serve that was dispatched past him by a fizzing Murray backhand.

The Scot carried the momentum to an immediate break but it quickly became clear service breaks would not be at a premium.

From 1-0 up, Murray found himself 4-1 down only to fight back to level.

Murray urged the crowd to be louder still as he tried to break in the ninth game but Djokovic held on, winning an amazing 29-shot rally and piling the pressure on his opponent.

Murray held twice to force a tie-break but made a poor start, trailing 4-0, and never recovered.

Murray had never beaten Djokovic from a set down and the world number one had never lost a match at Flushing Meadows from a set up, so the odds were firmly in his favour now.

Djokovic's record in New York is seriously impressive, with the 27-year-old looking to reach an eighth consecutive semi-final and a fifth straight final.

Murray looked in serious trouble when he dropped serve meekly in the third game of the second set but after three more service breaks they were level again at 4-4, Djokovic no doubt unamused by a time violation warning from umpire Pascal Maria.

Djokovic saved a set point at 5-6 to force a second tie-break, which had exactly the same pattern as the first but the other way around.

Murray looked to have the momentum and began the third set brilliantly, his flat, flashing forehand cutting Djokovic to pieces.

But he took his foot off the gas in the fourth game to go behind for the third successive set.

He had two chances to break back but this time his forehand just missed its target and Djokovic broke again to take a much more straightforward set.

Djokovic looked like the man who had won the big matches this season but Murray was certainly not out of it.

He had another break point in the opening game of the fourth set but Djokovic saved it, as he had all but four of the 16 chances Murray had had.

The extra time he had spent on court looked to be catching up with the eighth seed, who suddenly looked extremely tired.

He held serve surprisingly easily for the most part despite his back appearing to have tightened up, meaning he could not hit the ball at more than 100mph.

But with Murray serving to stay in the match at 4-5, Djokovic sensed his chance and sealed the victory when his opponent netted a backhand.