Stefanos Tsitsipas accidentally caught his father with his racket during an outburst at the ATP Cup on Tuesday during his match with Nick Kyrgios.
The Greek smashed his racket in anger after losing an opening-set tiebreak, and his swing caught Apostolos Tsitsipas, who was seated next to his son's chair as captain of the team.
The 21-year-old lost 7-6 (7), 6-7 (3), 7-6 (5) in Brisbane, Australia.
According to the Guardian, the world No. 6 played down the incident after his defeat.
"Maybe I'll [have to] stay in my room for three days," said Tsitsipas. "It happened accidentally. I didn't mean to do it and straight away forgot about it and moved on from there. It happens. I wasn't aiming to do that, it's just that it went out of control, unfortunately."