The world number trailed 0-5 to rival Carlos Alcaraz in the opening set of the showpiece on Monday (18.08.25) before his withdrawal, which comes just six days before the start of the US Open.

Sinner told the crowd: "I’m super sorry to disappoint you.

"From yesterday I didn’t feel great. I thought that I would improve during the night. It came up worse. I tried to come out and make it at least a small match but I couldn’t handle more. I’m very, very sorry for all of you. I know some of you on Monday maybe had to work or do something else, so I’m very, very sorry."

Sinner looked unwell throughout in 31C heat and 57 per cent humidity in Cincinnati and his condition only worsened during the match.

He requested the trainer at 0-4 down and decided to call it quits when he double-faulted to fall 0-5 behind.

The four-time major champion's withdrawal gave Alcaraz the first Cincinnati Open title of his career but the Spaniard admits that it was not the way he had hoped to triumph.

The world number two said: "As you said, Jannik, this is not the way I want to win matches, to win the trophy. I just gotta say sorry. I know and understand how you can feel right now. I can’t say anything you don’t know already, but as I say many times you are truly a champion. I’m pretty sure from this situation you’re going to come back stronger. You always do – that’s what true champions do. You really are one. Sorry and come back stronger."