Carlos Alcaraz won the ATP Cincinnati Open title on Monday after defending champion Jannik Sinner retired due to illness during the first set.
Meanwhile, Iga Swiatek defeated Jasmine Paolini in straight sets to lift the WTA Cincinnati Open women's crown for the first time on Monday.
Ailing world number one Sinner threw in the towel after Alcaraz roared into a 5-0 first set lead.
Italian ace Sinner said in an on-court interview afterwards he had started feeling ill on Sunday and his condition worsened overnight.
"I'm super super sorry to disappoint you," Sinner told fans. "From yesterday I didn't feel great. I thought that I would improve during the night but it got worse.
"I tried to make it at least a small match but I couldn't handle any more... so I'm very sorry to for all of you."
Alcaraz meanwhile expressed sympathy with Sinner, who gave no indication of the exact nature of his illness.
On the other hand, Six-time Grand Slam singles champion Swiatek battled through an error-strewn performance to win 7-5, 6-4 in 1hr 50min.
The victory extended Polish ace Swiatek's unbeaten record against Italy's Paolini to a perfect 6-0.
Swiatek's 24th career title was also her 11th trophy at the 1000 level, pulling to within two of all-time leader Serena Williams on 13.
But the 24-year-old was forced to dig deep for victory, rallying from a break down in the opening set to clinch her first Cincinnati title.
Swiatek struggled on serve throughout, and was broken four times by the seventh-seeded Paolini.
Paolini was unable to make the most of her openings though, and was broken six times as Swiatek closed out victory.
