Ryan Harrison has rejected accusations of racism made by Donald Young after a match between the two Americans at the New York Open.
Harrison, ranked 44th in the world, defeated Young 6-3 7-6 (7-4) in the first round of the ATP 250 event, the pair having confronted each other towards the end of the opening set.
Young later posted a message on Twitter suggesting he was the subject of derogatory remarks made by Harrison.
"I'm shocked and disappointed, Ryan Harrison, to hear you tell me how you really feel about me as a black tennis player in the middle of our NY match," he wrote.
"I thought this was supposed to be an inclusive gentleman's sport."
Harrison used the same social media platform to reject the accusations, calling for video and audio evidence to be produced to clear his name.
"The accusations made by Donald Young tonight following our match are absolutely untrue," he wrote.
"I'm extremely disappointed that someone would say this in reaction to a lost tennis match.
"Any video/audio will 100 per cent clear me and I encourage anyone with the available resources to find it."