Jack Draper admitted he is “quite an anxious human being” after vomiting three times in the biggest match of his life in the US Open semi-finals.

“Especially in these five-set matches that sort of anxiety and those feelings can build up,” he said.

The British No.1 refused to retire but went down 7-5 7-6 6–3 to world No.1 Jannik Sinner. The No.25 seed sweated profusely in the heat and humidity and had to change his rackets, shoes and shirt.

And he threw up on court during the 89-minute second set and needed a medical timeout. He had not dropped a set in his first five matches here.

Draper, who will now enter the world’s top 20, has previously admitted that stress has caused physical injuries because he is so tense.

And the 22-year-old admitted “I think obviously it’s a big occasion for me. I definitely felt, even though I generally feel pretty relaxed and stuff, I definitely felt more excited today, a few more nerves around.

“I’m definitely someone who is, I think, quite an anxious human being. I think when you add all that together sometimes I do feel a bit nausea on court, and I do feel a little bit sick when it gets tough.

“I didn’t have any problems before the match, but it obviously just built up.” Draper said he is learning to cope with the stress but is still working on becoming better mentally after playing 10 Grand Slams.

“Definitely I’m getting more and more experience as a player,” he said. “That’s the one thing that’s helping me this year and helping me to feel better in general is the more experiences you have of situations, the easier things become.

“You just take it all in your stride. Obviously Jannik’s been in this situation a few times now so he can sort of relate to maybe the feelings.

“It’s difficult. Obviously I’m an athlete, I’m a tennis player, and there are so many athletes out there. We’ve all got things we’re working through all the time. Tennis, or just any sport, is hugely mental and physical.

“I try my best all the time to keep on evolving, to keep on learning, and it’s definitely something I’ve had to just work through my whole entire life. I think I’ve got quite a strong mentality but I use up a lot of mental energy a lot of the time because I want it so badly.

“But obviously that doesn’t necessarily help a lot of the times, especially in these five-set matches and that sort of anxiety and those feelings can build up.

“So it’s definitely just something that, you know, is a real strength of mine but also a weakness, and I have to continue to work on it.”

Draper looked totally drained in the third set after his vomiting earlier in the match. “No, you don’t feel better,” he said.

“You just feel worse and worse, because you can’t put anything in your body. You know, like, when you’re playing long matches, you need to be able to drink and to eat things and,to give your body the supplies it needs to keep on going.

“But obviously when you’re feeling sick and stuff like that, you can’t put anything inside your body, because it just comes straight out, and it’s the worst feeling ever. You can’t move around the court when that happens.

“So no, it’s a horrible feeling, and you feel more dizzy and more sick the more you are. I am a big sweater on the court and it was extremely humid today. Hasn’t been pretty much the whole week as of yet.

“I think it was obviously a very physical match. Obviously that’s why Jannik is No. 1 player in the world, because when you play the top players, the intensity is different. You know, it’s a step up.”

But asked if had considered retiring from the match against the Australian Open champion, Draper insisted: “No, no, no, I’m not going to retire in the semis of a Grand Slam.

“I know the last set, it probably looked liked from courtside or on TV that it was not a great look. But, at the end of the day, I always try and give my best. The second set, I was feeling not too great, and I still pushed it to a tiebreak.

“I was fighting hard. I’m proud of myself. I tried to fight as hard as I can. Just not going to get it done against someone like that.”