Carlos Alcaraz debuted a bold new haircut ahead of his first-round U.S. Open match against Reilly Opelka Monday night.

No. 17 Frances Tiafoe continued a strong start by American men at the US Open, defeating Yoshihito Nishioka of Japan, 6-3, 7-6 (6), 6-3 on Monday to reach the second round at Flushing Meadows. Tiafoe, ...