Jannik Sinner has advanced to the Wimbledon quarterfinals despite hurting his right elbow on a fall and dropping the first two sets. That’s because Sinner’s opponent, Grigor Dimitrov, had to quit with an injured pectoral muscle. Sinner hadn’t dropped a set in the tournament until falling behind No. 19 seed Dimitrov 6-3, 7-5 Monday night. But at 2-all in the third set, Dimitrov stopped playing. It’s the third time Dimitrov failed to complete a Grand Slam match this season. He also did it at the Australian Open in January and the French Open in May.