Nishikori, a finalist at the US Open in 2014 withdrew from the Western & Southern Open; after a first positive test but would have hoped to recover in time.

"Just a little update, I just took another COVID test and am still positive. I have very minimal symptoms and am staying in full isolation in Florida," Nishikori posted on social media late on Friday.

"The next test will be early next week at which time we will update you with more information."

As a result, all eyes will be on his next test; but the Japanese ace could become the latest withdrawal and the first due to contracting COVID-19.

https://twitter.com/josemorgado/status/1296872396192976896?s=20