Postpublished at 23:24 British Summer Time 7 September 2018
Del Potro is up on his feet talking to the crowd and giving a post-match interview. He sounds emotional.
His head must be spinning.
Summary
Novak Djokovic to face Juan Martin del Potro in Sunday's final
Djokovic beats Kei Nishikori 6-3 6-4 6-2
Del Potro through after Rafael Nadal retires
Defending champion Nadal concedes because of knee injury
Argentine Del Potro led 7-6 (7-3) 6-2 when Nadal quit
Postpublished at 23:24 British Summer Time 7 September 2018
Postpublished at 23:23 British Summer Time 7 September 2018
Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extraDel Potro has had three surgeries on his wrist. It is bittersweet. It is a bad feeling seeing a champion being like that.
I think he stopped so we didn't have to remember him that way and he can play again in a few weeks time.
Postpublished at 23:23 British Summer Time 7 September 2018
Juan Martin del Potro is in the US Open final.
It wasn't the way he hoped to make it but after applauding Nadal down the tunnel, he breaks into a small smile and breathes a sigh of relief.
He has made it.
Postpublished at 23:22 British Summer Time 7 September 2018
David Law
BBC Radio 5 live sports extra commentator at Flushing MeadowsTerrible shame. It was one of the great sets of tennis in the first set.
It is a bittersweet moment for Juan Martin del Potro.
Nadal retirespublished at 23:22 British Summer Time 7 September 2018
Nadal 6-7 (3-7) 2-6 Del Potro
This is such a shame!
Nadal is heartbroken. He walks over to Del Potro, explains his reasoning and the Argentine tries to console him.
The defending champion waves to all corners of the court but quickly shuffles down the tunnel. He is absolutely devastated.
Postpublished at 23:21 British Summer Time 7 September 2018
Nadal 6-7 (3-7) 2-6 Del Potro
Oh hang on, Nadal is speaking to the trainer but it looks like he IS going to retire here...
Postpublished at 23:20 British Summer Time 7 September 2018
Jonathan Jurejko
BBC Sport at Flushing MeadowsEnd of set. End of Rafa? Not yet. He beckons for the trainer again and sits in his seat. No treatment yet, just a discussion with the medical man...
Postpublished at 23:20 British Summer Time 7 September 2018
Jeff Tarango
Former professional tennis player on BBC Radio 5 live sports extraIt is a tough call. Maybe Nadal thinks the gel will wear in in 10 or 15 minutes.
He is not grunting now and putting that extra 10% in.
Game and second setpublished at 23:20 British Summer Time 7 September 2018
Nadal 6-7 (3-7) 2-6 Del Potro
Nadal moves towards the net and sets up a volley smash. Del Potro's lob flies high and over the line.
But with the advantage, Nadal's forehand is overcooked and it brings up another deuce. He then thrashes another forehand into the net.
Set point number two for Del Potro... which he dispatches! The Argentine has an almighty lead now.
Postpublished at 23:18 British Summer Time 7 September 2018
Gigi Salmon
Radio 5 live sports extra commentator at Flushing MeadowsI think Nadal has said he is going to play on and that is why his box are shaking their heads.
Set pointpublished at 23:17 British Summer Time 7 September 2018
*Nadal 6-7 (3-7) 2-5 Del Potro
Nadal drives a forehand volley into court. 15-0.
The Spaniard then sends an ace down the line. 30-0.
But his forehand smashes into the net. 30-15.
And a double-fault - his first of the match - follows afterwards. 30-30.
Then Del Potro brings up set point...
Postpublished at 23:15 British Summer Time 7 September 2018
Jonathan Jurejko
BBC Sport at Flushing Meadows
Image source, AFPEarlier I joked in the press room that, with the make-up of the four semi-finalists, our anticipated long night might be cut shorter by an injury withdrawal.
Sorry in advance folks, if it happens...
Postpublished at 23:14 British Summer Time 7 September 2018
Gigi Salmon
Radio 5 live sports extra commentator at Flushing MeadowsNadal said "it's alright. I am going to retire but you are not right on this one" to James Keothavong in that exchange.
Postpublished at 23:13 British Summer Time 7 September 2018
Jonathan Jurejko
BBC Sport at Flushing MeadowsAnyone care to guess which player not to have ever been ranked world number one has beaten the man in that spot on the most occasions?
It's an easy one...
Of course it's Juan Martin del Potro.
He's already achieved nine wins over the world number one. Today could be number 10.
Del Potro holdspublished at 23:13 British Summer Time 7 September 2018
*Nadal 6-7 (3-7) 2-5 Del Potro
Del Potro looks comfortable here. He holds for love with an ace down the T.
Postpublished at 23:12 British Summer Time 7 September 2018
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End of twitter post 2Nadal holdspublished at 23:11 British Summer Time 7 September 2018
Nadal 6-7 (3-7) 2-4 Del Potro*
And he does hold. And doesn't retire... yet.
He's in position to attack Del Potro's serve.
Postpublished at 23:10 British Summer Time 7 September 2018
*Nadal 6-7 (3-7) 1-4 Del Potro
Del Potro is maintaining his level despite Nadal's visible drop on play. He smashes a backhand winner to cancel out Nadal's advantage.
It sounded like the Spaniard told the umpire "I am going to retire" on that last deuce. But he's battling hard to hold serve here...
Postpublished at 23:08 British Summer Time 7 September 2018
*Nadal 6-7 (3-7) 1-4 Del Potro
Nadal extends a rally and with each step, there's a grunt of pain. He eventually hammers his forehand into the net but is frustrated with the umpire.
He thinks there was a wrong call. But it's quickly deuce.
Postpublished at 23:06 British Summer Time 7 September 2018
*Nadal 6-7 (3-7) 1-4 Del Potro
Del Potro's forehand is called long and Nadal tells his opponent to challenge! He points to the sky and nods.
The Argentine does challenge and it's a good job he does because the ball is in. Talk about sportsmanship! 15-15.