Jannik Sinner was left ruing a badly-timed bout of illness after ailing during a five-set loss to Daniil Medvedev in the Wimbledon quarter-finals.

The world number one held his head in his hands after calling the doctor early in the third set and was helped off court for a medical time-out.

A possible retirement looked on the cards but Sinner gradually improved on the resumption and may have won the match had he taken one of two set points in the third.

He managed to force a deciding set but it was Medvedev who eventually claimed a 6-7 (7) 6-4 7-6 (4) 2-6 6-3 victory after exactly four hours.

Sinner said: “Already this morning I didn’t feel great. I had some problems. Then, with the fatigue, it was tough. I was dizzy quite a lot. Actually off court I had a little bit the toughest time maybe.

“I didn’t want to go off. The physio told me better to take some time because he watched me and I didn’t seem in shape to play. It was not an easy moment. I tried to fight with what I had today.”

The Italian was determined to finish the match and shocked himself that he came so close to winning.

“I was also surprised that I pushed the match longer,” he said. “I don’t want to retire if it’s only a little bit of illness or sick or whatever. I was still in shape to play somehow.

“The fifth set I felt a little bit better again. Today the energy level was not consistent. Like this, it’s also not easy to handle the situations on the court.

“I was never thinking about retiring. For sure the crowd helped me a lot, trying to push me. You don’t want to retire in a quarter-final of a grand slam.”

Sinner had won his previous five matches against Medvedev, including coming from two sets down in the Australian Open final, and he went into the clash as the favourite.

“I felt like I was playing some good tennis,” said Sinner. “I had tough opponents to reach this point. But it also gives you confidence when you beat certain players.

“It’s tough because I felt like that I was feeling the ball in a very positive way. Also today I tried. Just the ending was not what I wanted.”

Sinner had edged a very tight first set, taking it 9-7 on a tie-break after Medvedev double-faulted, but he began to look off colour during the second set and called the doctor after dropping serve to trail 2-1 in the third.

On the resumption he tried to shorten the points, frequently deploying the drop shot, and he got his reward for staying in touch when Medvedev played a loose game serving for the set at 5-4.

Sinner then had two set points in the Russian’s next service game but missed a makeable backhand on the second and it was Medvedev who took the tie-break this time, sealing it with an ace.

The momentum swung again when Sinner clinched a quick fourth but it was Medvedev who was stronger in the big moments in the decider.

The fifth seed has already equalled his best run at Wimbledon and, if he is to go further, he will have to reverse the result of last year’s semi-final when he takes on Carlos Alcaraz on Friday.

Medvedev said: “For me, what was important today is I lost five times to him. It was important to come out today and show that, look, we’re going to play probably many more times if we are both on tour, probably semis, quarters, finals, whatever.

“It was important to just show I’m always going to be there, I’m always going to fight, I’m always going to try to make your life difficult. Maybe you’re going to win more, maybe I’m going to win more, I don’t know, but I’m going to fight.

“That’s the same with Carlos last year in the US Open. That’s going to be the same with Carlos in a couple of days.”