In a video of the moment, it looked as though the 34-year-old Dimitrov injured a pectoral muscle on a volley. Almost immediately after the hit, he fell to the ground, clutching the right side of his chest in pain.

Grigor Dimitrov retired from his Wimbledon match against Jannik Sinner with a two-set lead on Monday, with an injury costing him a potential upset against the world No 1.

Jannik Sinner is through to the Wimbledon quarterfinals, though not in the way he wanted. Sinner lost the first two sets of his fourth-round match with Grigor Dimitrov on Monday before Dimitrov was forced to retire from the match after suffering an apparent pectoral injury.