The four-time Major winner subsequently pulled out of the US Open’s new mixed doubles competition, where he was expected to pair up with doubles world No. 2 Katerina Siniakova.
But his coach has now confirmed that he should be ready in time for the main event, and will soon be back on the practice court.
Cahill, who also works for ESPN alongside his coaching job, told the sports channel: “I spoke briefly with him last night. He was feeling a little better.
“He’ll rest, that’s the plan, and I hope he can get on the court on Thursday and start hitting some balls. We’re confident he’ll be fine.”
Cahill watched on with concern as Sinner gingerly walked around the court in the Cincinnati Open final, attempting to cool himself down with a bag of ice before he eventually retired.
The world No. 1 then apologised to the fans and paid tribute to his team in a downbeat runner-up speech. “Usually I’d start with the opponent but today I have to start with you guys,” he told the crowd.
“I’m super super sorry to disappoint you. From yesterday, I didn’t feel great. I thought it would improve during the night but it came up worse.
“I tried to make it at least a small match but I couldn’t handle more. I know people on Mondays have to work and do something else, so I’m really really sorry.”
Addressing Cahill and the rest of his coaching camp, Sinner added: “To my team, thank you for pushing me every day because it’s not easy when we travel around the world the whole year.
“Thank you for understanding the situation today. I’m very sorry to disappoint but sometimes it’s like this and we have to accept it.”
Sinner is the reigning champion at the US Open, beating Taylor Fritz in last year’s final. He now has a few days to get back to work in Flushing Meadows before starting his title defence.
To be the first to receive the latest tennis news, join our WhatsApp community or newsletter