Greek tennis player Stefanos Tsitsipas said he accidentally hit his father, who is also his coach, when he angrily swung his racket during an ATP Cup match Tuesday.

Tsitsipas’ father, Team Greece’s captain Apostolos Tsitsipas, had a visible bruise on his arm when he got up from his courtside seat holding his arm to sit with the rest of the Greek team in the stands.

The 21-year-old's mother was quick to come down from the stands to give her son an earful.

“Maybe I’ll stay in my room for three days, grounded by my father,” he joked to reporters later.

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Tsitsipas lost his cool after he lost the opening set tiebreak with Nick Kyrgios, 24, from Australia.

“It happened accidentally, I didn’t mean to do it and straight away forgot about it and moved on from there,” he said. “It happens, I wasn’t aiming to do that. It just went out of control, unfortunately."

He was docked a point and warned by the umpire.

This is not Tsitsipas’s first outburst on the court. Last summer, he accused a U.S. Open umpire of bias.

"I don't know what you have against me," he said to the umpire who told Tsitsipas it was time to play while he was still getting ready. "Because you're French probably and you're all weirdos! You're all weirdos!"

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Tsitsipas is ranked sixth in the world.

The Associated Press contributed to this report.