Coco Gauff was left in tears after getting into an extended argument with the chair umpire over a ruling during the reigning U.S. Open champion's 7-6 (7), 6-2 loss to Donna Vekic of Croatia in a Paris Olympics third-round singles match Tuesday.

World number two Gauff claimed she was "getting cheated" over a line call in the sixth game of the second set.

Gauff hit a serve and Vekic's return landed near the baseline. A line judge initially called Vekic's shot out; Gauff did not keep the ball in play. Chair umpire Jaume Campistol thought Vekic's shot landed in and awarded her the point, giving her a service break and a 4-2 lead.

She then walked over to talk to the official, and play was delayed for several minutes.

"I never argue these calls. But he called it out before I hit the ball," Gauff said to Campistol. “It’s not even a perception; it's the rules. I always have to advocate for myself.”

Gauff, a 20-year-old from Florida, was seeded second in Paris and easily won her first two singles matches, dropping a total of just five games.

But her first Olympic singles tournament – she is still in women's doubles and mixed doubles – ended with a performance that was hardly her best on the hottest day of the Summer Games so far, with the heat rising above 32 degrees celsius.

Even before the trouble over the umpiring decision, Gauff could not sustain a good start against Vekic, who was a semifinalist at Wimbledon this month. (AP/AFP)