Tennis pro Donald Young accused opponent Ryan Harrison of making racist remarks during a match Monday at the New York Open.

During a changeover in the first set of Harrison’s victory over Young 6-3, 7-6, the two Americans engaged in a heated argument before the umpire attempted to resolve the issue. After the match, Young, from Atlanta, Ga., tweeted that he was disappointed in Harrison’s behavior during the dispute.

"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," Young wrote on Twitter after the match. "I thought this was supposed to be an inclusive gentleman's sport."

Harrison later denied the accusation on Twitter, writing, "The accusations made by Donald Young tonight following our match are absolutely untrue. I'm extremely disappointed that someone would say this in reaction to a lost tennis match. Any video/audio will 100% clear me and I encourage anyone with the available resources to find it."

The tour is investigating the incident, according to Deadspin.