That was a bit of an epic match, and not always in a good way.
Juan Martín del Potro - John Isner
US Open men - 4 September 2018
US Open – Follow the Tennis match between Juan Martín del Potro and John Isner live with Eurosport. The match starts at 18:30 on 4 September 2018. Our live coverage lets you follow all the key moments as they happen.
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Del Potro will face the winner of today's next men's singles match - Rafael Nadal or Dominic Thiem.
Del Potro tells the New York crowd that the US Open is his favourite tournament.
DEL POTRO 6-7(5) 6-3 7-6(4) 6-2 ISNER: There's a nice hug between the pair at the net as Isner nets his last shot, and Del Potro allows that famous beam to cross his face after three and a half hours of gruelling tennis.
DEL POTRO 6-7(5) 6-3 7-6(4) 5-2 ISNER: Delpo is raring to get back to his seat, ready for the massage from the trainer.
DEL POTRO 6-7(5) 6-3 7-6(4) 4-2 ISNER: Isner noted that problem with Delpo's leg and is going to try and make him move.
Del Potro seems to have some stiffness in his left leg.
DEL POTRO 6-7(5) 6-3 7-6(4) 4-1 ISNER: Isner has a break point here and then lashes his return much to his massive frustration.
DEL POTRO 6-7(5) 6-3 7-6(4) 3-1 ISNER: Gritty from Isner, who looks exhausted but is summoning up his last reserves.
DEL POTRO 6-7(5) 6-3 7-6(4) 3-0 ISNER: And then a straightforward hold of serve for Del Potro who's looking much more composed now.
DEL POTRO 6-7(5) 6-3 7-6(4) 2-0 ISNER: There's the break! Del Potro is crushing the return backhand.
DEL POTRO 6-7(5) 6-3 7-6(4) 1-0 ISNER: That's the start to the fourth set the Argentinian wanted!
Isner opts to invoke the ten-minute heat break, unsurprisingly. Time for some air-conditioning.
DEL POTRO 6-7(5) 6-3 7-6(4) ISNER: Isner shouts at his racquet after he fails to return a Del Potro mishit, and then the third seed steps it up on serve. Another mini-break follows before he serves out the set.
DEL POTRO 6-7(5) 6-3 6-6 ISNER: Another tie-break, then? Yes.
DEL POTRO 6-7(5) 6-3 5-6 ISNER: Isner isn't happy with Delpo's rowdy friends in the stands, and that fires him up a touch more.
DEL POTRO 6-7(5) 6-3 5-5 ISNER: Hold to love for Delpo, and Isner breathes deeply as he prepares for his own service.
DEL POTRO 6-7(5) 6-3 4-4 ISNER: Del Potro allows the power of Isner to blister past him and prepares for his serve.
DEL POTRO 6-7(5) 6-3 4-4 ISNER: Hold to love for Del Potro.
DEL POTRO 6-7(5) 6-3 3-4 ISNER: Isner's summoning up some power to avoid having to rally - he looks very hot and tired.
DEL POTRO 6-7(5) 6-3 3-3 ISNER: Isner can look threatening on these return games but there are too many errors - is he simply suffering in the heat?
DEL POTRO 6-7(5) 6-3 2-3 ISNER: Del Potro rushes to the net and fails with a drop shot, handing Isner game point.
DEL POTRO 6-7(5) 6-3 2-2 ISNER: Isner may come to regret his failure to break the Delpo serve there, as the Argentinian reverses strategy, going in on his opponent's forehand.
DEL POTRO 6-7(5) 6-3 1-2 ISNER: Isner is targeting the Delpo forehand again, which didn't work in the last set.
DEL POTRO 6-7(5) 6-3 1-1 ISNER: Del Potro has a group of very rowdy fans cheering him on now as he holds serve.
DEL POTRO 6-7(5) 6-3 0-1 ISNER: Belting serving from Isner past a despairing Del Potro.
Delpo will probably go and change his shorts now.
DEL POTRO 6-7(5) 6-3 ISNER: A hold to love for the 2009 US Open champion to even things up on serve.
DEL POTRO 6-7(5) 5-3 ISNER: Isner double-faults on game point but gathers his composure to serve out eventually.
DEL POTRO 6-7(5) 5-2 ISNER: Game Del Potro with another biff of a first serve.
DEL POTRO 6-7(5) 4-2 ISNER: Blistering serve from Isner on the advantage to hold serve.
DEL POTRO 6-7(5) 4-1 ISNER: Isner doesn't even move towards Del Potro's final ace, straight down the line.
DEL POTRO 6-7(5) 3-1 ISNER: Annoying shorts or no annoying shorts, this is a great break for Delpo, as Isner misses his first serve.
(He is not allowed to go off court to change his shorts. He suggests he changes them on court. That too is rejected.)
DEL POTRO 6-7(5) 2-1 ISNER: Del Potro is complaining about something again - sounds like he wants to go off court to change his shorts.
DEL POTRO 6-7(5) 1-1 ISNER: Del Potro has break point but Isner sends his next serve a little wider, beyond his reach.
DEL POTRO 6-7(5) 1-0 ISNER: Del Potro spends the time between sets complaining about something. He then holds serve.
DEL POTRO 6-7(5) ISNER: First set to the American, who pounces on slower serves to gain the mini-break before serving it out himself.
DEL POTRO 6-6 ISNER: To a tie-break it is - and I think we could have predicted that.
DEL POTRO 5-6 ISNER: More excellent play at the net, with Isner playing beautifully across Del Potro to hold serve.
DEL POTRO 5-5 ISNER: Delpo mixing up his serve speed now and doing well on the second.
DEL POTRO 4-5 ISNER: Isner is serving at over 130mph at the moment. Incredible.
DEL POTRO 4-4 ISNER: Another good hold for the Argentinian.
DEL POTRO 3-4 ISNER: A rocket of a forehand from Del Potro down the line at 102mph, but Isner still holds.
DEL POTRO 3-3 ISNER: Absolutely belting serving from Juan Martin Del Potro - although both first and second are slower than Isner's at the moment.
DEL POTRO 2-3 ISNER: Another hold of serve, which is probably going to be the way things go during this match, let's face it.
DEL POTRO 2-2 ISNER: Delpo sends his forehand down the Isner throat.
DEL POTRO 1-2 ISNER: Again, Isner's going after the Delpo forehand with his first serve.
DEL POTRO 1-1 ISNER: Isner is still using that volley to attack the Del Potro forehand, which is brave but risky.
DEL POTRO 0-1 ISNER: Nice volley at the net from Isner to level things up at 30-all after a shaky start on his serve.
Isner to serve.
The players are heading out on to court.
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