India, Aug. 30 -- American fans at the US Open, and thousands watching the tournament on TV, were hit by back-to-back losses when Ben Shelton and Frances Tiafoe exited in consecutive third-round matches on Friday. While Shelton was forced to retire due to a shoulder injury, Tiafoe suffered an unexpected loss.

Shelter, the No. 6 seed, was visibly struggling with his shoulder during the fourth set of his match against Frenchman Adrian Mannarino. The American was leading and cruising towards a much-needed win before he tumbled. The 22-year-old continued playing, but the pain ultimately forced him to retire, handing his opponent a walkover.

'Usually I play through'

While no specifics were revealed, Shelton said, "Usually, I'll play through...