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.

Carlos led 20-14 in service winners and dominated the baseline 36-20. He landed 28 winners and 24 unforced errors, sailing over the top and prevailing for the ultimate test with more hours on the practice court.

The second spot in the 2025 Cincinnati Open men’s singles final is on the line Saturday night, as No. 2 Carlos Alcaraz battles No. 3 Alexander Zverev.

Ten seeded players were in action during the Cincinnati Open quarterfinals Aug. 15. Here's how the action unfolded in Mason.