Speaking before he walked onto the court for his US Open semi-final showdown with Jannik Sinner, British number one Jack Draper offered a prescient prediction.

“I’m going to have to play some incredible tennis... going to have to compete like an animal out there,” he said.

On a humid night in New York, the level of competing required was surely more physical than even Draper expected, as he sweated his way through shirts and shoes before having to clean up his own vomit on the baseline after twice throwing up during the second set.

The best part of two-and-a-half hours had been played by the time Sinner breezed through a tie-break at the end of that set to close in on victory, the race appearing to be increasingly run for an exhausted Draper, and so it proved.

Sinner ruthlessly moved towards the finish line, wrapping up a 7-5 7-6 6-2 win. He will face either Taylor Fritz or Frances Tiafoe in Sunday’s final.

That a straight-sets victory took a little over three hours pointed to a extraordinarily gutsy effort from Draper, who from near enough the first game appeared to be battling the conditions and his body, as well as his close friend on the other side of the net. Dripping with sweat throughout, he struggled to grip his racket as early as the first set.

Draper will move into the top 20 of the world rankings for the first time after his career-best run at a Grand Slam, one that provided plenty of evidence he is ready to step up as Britain’s leading man in the post-Andy Murray era.

Unwanted pre-match interviews completed, the pair exchanged six routine, if slightly nervy, holds to start the match, before Sinner landed the first blow. He brought up break point and took the 4-3 lead as Draper whipped a forehand wide, but the response from the Briton was immediate.

Sinner produced an uncharacteristically loose game, his forehand suddenly deserting him, as Draper raced 0-40 up and broke straight back at the third time of asking.

At 5-4, Draper was just a couple of points away from taking the opening set, but the pressure was swiftly back on him after Sinner held. Draper saved two break points, only to then offer up a succession of double faults, his racket seemingly slipping in his hand due to the sweat. Sinner made no mistake in serving the set out after that gift, Draper having already made six double faults.

“Look for the shorter points - not easy, but you’ve got to,” was the message from Draper’s coach James Trotman, aware his man was enjoying little success in the longer rallies.

Try as Draper might, there was nothing short about the early exchanges of the set. The first three games took half an hour, nothing coming easy for Draper, who cut an increasingly weary figure. He saved break points in each of his first three service games, somehow keeping Sinner at bay despite his problems increasingly growing.

Trotman told him to change rackets after his hand slipped for the latest double fault, advice which was ignored by Draper until another one immediately followed. He was then forced to put on a new pair of shoes, having waterlogged his initial pair, as the ball kids were put to work in attempting to dry the court, but Draper still kept it on serve to lead 4-3.

He produced a stunning drop volley in the next game, calling for more noise from the crowd and duly getting it, but a stunned silence then followed as Draper threw up on the baseline between points in a frankly ridiculous end to the set.

Sinner won arguably the best point of the tournament, having falling over awkwardly and then recovered to produce an absurd winner from a Draper smash, though that left him needing treatment on his wrist at the next changeover. Draper, meanwhile, received attention from a doctor at the same time, while also attempting to remember his locker number so another pair of shoes could be retrieved.

With one bent over battling sickness and the other stretching his wrist out with worried glares to his box, it was compulsive viewing. The set felt must-win for Draper, as it went to a tie-break, but Sinner raced into a 4-0 and never looked back.

Draper’s tank had long been emptied and the third set was a question of when, not if, Sinner pulled away. The Briton managed two gutsy holds before the top seed got his break, Draper by now almost a spectator as he watched the winners fly past.

Sinner raced through to a 5-2 lead as Draper stepped up to serve to stay in the match, his late order of a Coke doing little to raise the energy levels. A backhand return winner from Sinner to finally see off his friend felt like an act of mercy.