Czech teenager Jakub Mensik, who stunned Novak Djokovic in the Miami Open final on Sunday, said had it not been for a referee taking a timely lunch, he would have pulled out of the tournament before his first match.
Mensik, who won his first ATP tour title with the victory, said he suffered intense pain in his right knee during practice and could barely walk, let alone run.
The 19-year-old said that he had filled out his withdrawal form ahead of his match with Spaniard Roberto Bautista Agut and went to the referee's room – but the official was out for lunch.
"I was like okay, well let's just visit the physios. I told them, 'my knee is hurting, I filled out the paper and I'm going,'" Mensik told reporters.
"The physio said let's see and he started to do a couple of treatments, he took care of it for like 30 minutes. He said it is nothing serious and you can play with this pain and nothing will happen," he added.
But Mensik said, while the ref was eating lunch, he returned to the treadmill and was still in agony.
"I was really suffering. I took a different painkiller, switched it up a bit and started to feel a little relief. It was 30 minutes before the match, I thought 'I can walk, I can run, let's see.'"
Mensik won the match in three sets, beginning a run at Miami which saw him beat Indian Wells champion Jack Draper and – in the semifinal, world No 4 Taylor Fritz.
It was a tournament which showed the teenager's huge potential and Mensik, who said emulating Djokovic had been his motivation for starting his career, wrote on the camera lens "First of many" as he left the court.
"Of course, right now, it's the biggest win of my career so far, and I'm just super happy with that, but I know that this is not the end, I know that this is just the beginning for me, and I'm still 19 years old, so I have all my career in front of me," he said.
"Of course it feels really great to have this trophy next to me, but it's not just about the one title, one tournament.
"Now I will celebrate, rest, when I will get back home, I'm going back to work, and will try to get better and better, because still there is a lot of space for improvement in my game, so I and my team will do our best to lift these trophies more often," he said.
Mensik was not even born when Djokovic played in his first ATP Masters 1000 event, a fact that, when pointed out to him, led Mensik to put his head in his hands.
"And he's top five still. So it's just crazy and unbelievable what he's achieving in this sport during long period of the time," he said.
"Imagine me in 20 years from now, which I will be 39 playing the finals? I hope so, but it's crazy, to think about it like this."