Sinner retired with apparent illness in the first set of Monday's Cincinnati Open final against Alcaraz after digging a 5-0 deficit. Sinner remained on the court for the trophy ceremony and addressed his condition while speaking with the crowd. He didn't offer specifics, but said that he "didn't feel great."

Carlos Alcaraz won the Cincinnati Open on Monday after Jannik Sinner was forced to retire due to illness. Alcaraz was already up big on Sinner, the World No. 1, when he had to retire. Sinner told the crowd that he hoped to play after feeling bad overnight, but he couldn't make it work.

Fierce rivals Carlos Alcaraz and Jannik Sinner square off at the men's Cincinnati Open Final today. Find out how to watch for free.