Sinner advances to US Open fourth round, defends title.

Jannik Sinner kept his U.S. Open title defense firmly on track on Saturday in New York, rallying from a set down to beat Denis Shapovalov 5-7, 6-4, 6-3, 6-3 and reach the tournament’s fourth round at the USTA Billie Jean King National Tennis Center. The victory followed earlier straight‑set wins over Vit Kopriva and Alexei Popyrin, and came less than two weeks after Sinner was forced to retire from the Cincinnati Open final with illness.

Sinner opened his Flushing Meadows campaign with a 6-1, 6-1, 6-2 first‑round win over qualifier Vit Kopriva and followed that with a 6-3, 6-2, 6-2 dismantling of Popyrin in the second round. Those matches helped dispel concerns about his fitness after the mid‑August withdrawal in Cincinnati and his subsequent withdrawal from the U.S. Open mixed doubles. “I’m very happy that I’m healthy again,” Sinner said after his opening match, adding that a few good practice days had put him “in the best possible shape” for New York.

Saturday’s test from Shapovalov proved far sterner. The Canadian snatched the opening set and at one stage threatened to pull further clear, earning a contentious foot‑fault call that prompted an exchange with the chair umpire....