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.

Jannik Sinner has advanced to the Wimbledon quarterfinals despite hurting his right elbow on a fall and dropping the first two sets.

Dimitrov was playing fantastic tennis, running Sinner around the court and delivering booming serves. Dimitrov won the first set 6-3 and survived a hard-charging comeback attempt from the Italian in the second to take the set 7-5 and put the world No. 1 in a desperate position.