Juan Martin del Potro reached the semi-finals for the third time in the last five grand slams after coming through a gruelling battle with John Isner.

The two big men battered each other to near exhaustion in the humidity of Arthur Ashe Stadium but it was Del Potro who proved the stronger in a 6-7 (5/7) 6-3 7-6 (7/4) 6-2 victory that lasted three-and-a-half hours.

The popular Argentinian will now attempt to take a step he has not managed since winning his only grand slam title here nine years ago and reach another final.

Juan Martin del Potro
Del Potro serves during the quarter-final (Andres Kudacki/AP)

In among the wrist surgeries and long lay-offs, Del Potro has made three semi-finals, losing to Novak Djokovic at Wimbledon in 2013 and then Rafael Nadal here last year and at the French Open this summer.

He then pushed Nadal all the way in a classic Wimbledon quarter-final and could well get another crack at the Spaniard, who was due to face Dominic Thiem in the night session on Tuesday.

Del Potro said: “I’m so happy to reach another semi-final in my favourite tournament that’s very special to me.

“Of course beating John in this kind of match is like an epic. We both were tired in the end, we both fought until the end and I think I survived with my serve. That was the only difference I think.”

The extreme heat policy was again in effect and conditions were so hot at the start of the contest that all junior matches were suspended.

The players took a 10-minute break at the end of the third set, and Del Potro said: “I lay down on the table and I didn’t want to come back again because with this heat it’s impossible to play tennis.”

Del Potro’s cheer squad, a group of friends who have travelled from his home town of Tandil, were again a noisy presence, attracting the ire of Isner at one point in the third set.

Del Potro now has two days off before the semi-finals but will be keeping to himself, saying: “If I met them it could be dangerous for me. We will have time to have fun together.”

Isner, who is having the best season of his career, was looking to reach his second consecutive slam semi-final and in doing so become the first American semi-finalist in the men’s singles here since Andy Roddick in 2006.

Many players have been driven to distraction by the small margins involved when playing Isner and one backhand that just drifted into the tramlines cost Del Potro the opening set – the first set he has lost all tournament.

The Argentinian had only won three of his last seven meetings with Isner but gained the break he needed early in the second set and maintained his advantage.

There were few of the thunderbolt forehands for which Del Potro is most famous, the third seed instead seemingly trying to conserve as much energy as possible.

Both players had two chances to break in the third set, and the 15-40 chance that Isner missed at 2-1 ultimately proved to be his big opportunity.

The American was not landing enough first serves to keep himself out of trouble, with Del Potro increasingly forcing him to play off his toes, and by the fourth set Isner’s resistance had run out.

Isner got through 11 shirts and estimated he lost between eight and 10 pounds.

He echoed Roger Federer’s thoughts on the roof structure making Ashe more humid, saying: “It’s tough conditions out there, no doubt. It’s very humid. The air is pretty still for whatever reason. Maybe it’s the roof structure.

“He probably handled it a little bit better. I wish I could have done a little bit better out there. It just wasn’t to be. He’s so good. It was a tough match.

“I have never seen Roger sweat, ever. If he’s sweating a lot and has to change clothes, then you know it’s pretty humid out there.”