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.

Dimitrov & Jannik Sinner share an embrace as Grigor retires from their match at Wimbledon due to injury Grigor has had to deal with so much over the last few years Hard to watch this happen to anyone, especially someone as kind & hardworking as him 💔 pic.twitter.com/2k7gXAxgDq

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.