US Open: Nishikori edges Murray in five-set thriller

At the end of an encounter that was as gripping for the spectators as it was grueling for the players, Nishikori raised his fists to the air in triumph as Murray, the No. 2 men's player, swiftly exited the court, stopping only to sign a couple of autographs.

A shade over four hours earlier. Nishikori almost got off to a dream start, taking a 0-40 lead in the opening game before Murray came roaring back to hold serve. Nishikori won his first service game too. But that was as good as it got for Nishikori in the first set as Murray found his best form, breaking his opponent's serve twice to seal a ruthless 6-1 first set win.

The players traded blows at the start of the second set, with Nishikori showing increased attacking intent before a brief rain break at 3-3. The interlude seemed to galvanize the underdog still further - Nishikori broke Murray to love in the ninth game before holding serve to tie the match at 1-1.

Murray, who won this year's Wimbledon tournament after losing the Australian and French Open finals to Novak Djokovic, looked to be pulling away again when he took the third set to lead 2-1, with Nishikori hitting a series of unforced errors at crucial times.

The pendulum swung once more in the fourth set, with Murray making mistakes. Nishikori pounced to give himself a great chance of making his first Grand Slam semifinal since he lost to Marin Cilic of Croatia in the 2014 US Open.

Nishikori struck first in the final set as the game clock ticked past three hours. He broke serve in the first game, only for Murray to level things up three games later. The players exchanged breaks again later in the set before Nishikori earned himself the chance to serve for the match, much to Murray's frustration - the Scot hammered the net cord with his racquet.

But Nishikori wasn't to be denied this time as Murray dumped a routine backhand in to the net and sparked Japanese celebrations.

The Japanese player, a beaten finalist in this tournament in 2014, moves on to play Stan Wawrinka in the last four on Friday. The Swiss No. 3 in the world defeated Juan Martin del Potro of Argentina 7-6 (5),4-6, 6-3, 6-2 to advance.

Quick turnaround for Serena

On the women's side, Serena Williams of the United States beat the No. 5-ranked Romanian Simona Halep 6-2, 4-6, 6-3 to advance to the semifinals. The world No. 1, seeking a record seventh US Open title and 23rd Grand Slam crown, is to face first-time Grand Slam semifinalist Karolina Pliskova of the Czech Republic on Thursday.

"The whole year you play every single day," Williams said, "so this is totally normal," Williams said, playing down the relatively quick turnaround.

Pliskova defeated the Croatian,Ana Konjuh, 6-2, 6-2 in the other quarterfinal played on Wednesday.

In Thursday's other semifinal, Germany's Angelique Kerber, who is bidding to replace Williams as No. 1 in the rankings, faces Caroline Wozniacki of Denmark.