Jannik Sinner, Novak Djokovic battle injury worries ahead of Wimbledon quarter-finals

Sinner fell early in his match against Grigor Dimitrov and he was in real danger of being beaten in three sets before Dimitrov was forced to retire with a pectoral injury.

The world No 1 received treatment for his elbow problem on court and admitted in his press conference that he is waiting to see how it reacts ahead of his next match.

"It happened very early in the match, first game. It was quite an unfortunate fall," said Sinner.

"Checked the videos a little bit, and it didn't seem tough one, but I still felt it quite a lot, especially serve and forehand. I could feel it. So let's see. Tomorrow we are going to check to see how it is, and then we see."

Sinner headed into Wimbledon without his own physio after the exit of trainer Marco Panichi and physiotherapist Ulises Badio from his team, but he is confident the ATP Tour staff working at the All England Club will help him to get fit for the rest of the tournament.

"Yeah, here they have good ATP physios, in any case. The doctor's good," he said. "As I said, tomorrow we are going to check with MRI to see if there's something serious, and then we try to adjust it."

Sinner went on to explain why Dimitrov had given him so much trouble, as he paid tribute to his opponent after his unfortunate retirement.

"He served incredibly well. Very precise, also very fast," said Sinner. "Changed up the game very, very good.

"It was a bit breezy, and he used the wind in the best possible way. I could feel that he prepared the match in a very good way, and he executed even better. Yeah, he was playing some great tennis. After the roof closed, you don't know what's happening.

"There were some good rallies in the beginning of third set. But yeah, I mean, I tried to stay there mentally. I broke him back on 5-4.

"Then he played, again, lights out tennis to break me back. Yeah, I think he's showing his potential. It's very unfortunate, as I said on court. I wish him a speedy recovery."

Meanwhile, Djokovic was spotted practising at Wimbledon on Sunday with the grey knee brace he used after he underwent surgery just before Wimbledon last year.

He may use the knee brace as a precaution in practice, as it was not in evidence as he played out a tense four-set win against Alex De Minaur.

Djokovic has been in sparkling form throughout Wimbledon, but he was not at his best against Di Minaur and insisted after the match that he was not carrying an injury. 

READ MORE: Cruel twist for Dimitrov as injury halts Wimbledon masterclass against Sinner