Stan Wawrinka overcame the huge challenge thrown at him by Juan Martin del Potro to reach the US Open semi-finals with a four-set win.

The Swiss third seed ended a four-match losing streak against Argentinian Del Potro with a 7-6 (7-5) 4-6 6-3 6-2 victory at Arthur Ashe Stadium on Wednesday.

It took him three hours, 12 minutes, but Wawrinka is into the last four in New York for a third time in four years.

The two-time grand-slam champion will take on Kei Nishikori, who upset Andy Murray in their quarter-final.

For Del Potro, whose career was threatened by injuries, the loss ended his best run at a major since Wimbledon in 2013.

The Rio Olympics silver medallist tired late in the clash after pushing Wawrinka in a hugely entertaining encounter that finished after 01:00 local time (05:00 GMT).

After calling a trainer during the first set, Wawrinka came from 4-1 down to force a tie-break.

He immediately took control of the tie-break before Del Potro saved a set point with a brilliant forehand cross-court pass.

However, much to his disbelief, he sent a forehand into the net to give up the first set and was left with his head in his hands.

Del Potro also broke first in the second set, and this time he made the most of it despite a struggle to level the match.

Wawrinka responded in the third, breaking after a lengthy eighth game as 16 winners saw him regain the upper-hand.

He broke to start the third and again when he ripped a backhand down the line for 3-0, as he took complete control against a tiring Del Potro.

Despite being urged on by some passionate fans, Del Potro was beaten – Wawrinka with a backhand winner to close out his victory.