Jack Draper blamed stress for the physical struggles that led to him vomiting in a courtside bin at the end of his five-set win over Marcos Giron.

It is a measure of how inexperienced the 22-year-old still is at the highest level that he had never previously played a match that went the distance, and he looked in serious trouble at two sets to one down against American Giron in 31 degree heat at the Australian Open.

But Draper has been working hard on his physical conditioning and it paid off as he fought back to win 6-4 3-6 4-6 6-0 6-2 after three hours and 20 minutes.

As soon as he had shaken hands with Giron after a final gruelling rally he ran to the bin to be sick and it was several minutes before he was able to walk off the court.

“It was weird,” he said. “I obviously played such a long point, maybe it was sort of a reaction to finally getting over the line. I don’t know. I kind of felt bad because I obviously just beat the guy, and I was saying, ‘I need to shake your hand, mate, but I need to get to that bin’.”

Draper was left with mixed feelings, saying of his physical conditioning: “I’m obviously nowhere near where I want to be still, but it’s coming. For sure I would have cramped in these matches last year, even maybe four months ago.

“It was obviously a physical match. It’s tough conditions. It wasn’t that long for a five-set match. I played three hours 40 (minutes) last week in hotter conditions and I was physically absolutely fine.

“It’s obviously a grand slam. It’s tougher sort of with the tension to play that first match. I think I’m still a young player, so getting used to the environment around these slams and the tension is difficult.

“There’s no doubting I’m really proud to come through this match and I think it is really important for me.

“But there’s still some underlying stuff that obviously I need to work on, whether that be psychologically starting these slams or just the way I’m handling the anxiety and the nerves because I obviously don’t want to play a match like that where I feel like I’m on my hands and knees a lot, and I’m struggling to breathe and calm myself down. That’s not a positive.”

The match was dominated by punishing rallies from the start and, after edging the first set, it became clear in the second that Draper was struggling.

He called the trainer at the end of the set and had his blood pressure and pulse taken, and Giron looked odds on to win when he clinched the third.

Draper headed off court at that point to change his clothes and revealed in his press conference later that a talk in the mirror helped him achieve the dramatic turnaround that followed.

“I’ve heard (Novak) Djokovic say it a few times in his career,” said Draper. “He has gone two sets to love down and he has a go at himself. I think it’s important to not dwell on it.

“I kind of just looked at myself in the mirror and said, ‘Come on, we need to try and do this. I know it’s going to be two sets now, and give it your all. It’s the Australian Open. Only going to be here once this year’.”

Draper will hope to have enough time to recover ahead of his second-round clash with Tommy Paul – who he beat last week on his way to the final of the Adelaide International – on Thursday.

There were more straightforward wins for Cameron Norrie and Katie Boulter on a very good day for the British contingent.

Norrie dispelled concerns over the wrist problem that forced him out of last week’s tournament in Auckland with a routine 6-4 6-4 6-2 victory over Juan Pablo Varillas, while Boulter defeated Yuan Yue 7-5 7-6 (1).

The British number one missed two match points serving for the match at 5-4 in the second set, one with a double fault and the other an unforced error, but put the setback behind her to dominate the tie-break.

“It wasn’t easy at all,” said Boulter. “I felt like that was my moment to really dig in, take a deep breath and start again. It took a lot of strength to come back from that.

“I feel like I relish that situation because I know how tough I am and I know that I can get myself out of it.

“I managed to bring some of the better tennis that I played of the day out in the biggest moment. I think, if I’ve learned anything over these years, that’s what the best players in the world do.”

It was not quite a perfect day, with Dan Evans beaten 4-6 7-6 (8) 6-1 7-6 (4) by Italy’s Lorenzo Sonego.

The British number two took heart from his display, though, having come into the tournament short on fitness following a torn calf in October.

“I made the decision to come and play in Australia rather than stay home and practise and get fit that way,” said Evans. “So I knew I was maybe not going to win so many matches here, and that’s obviously been proven correct. It’s all good moving forward to get stronger.”