American tennis player Jared Donaldson was involved in a angry confrontation with umpire Arnaut Gabas after the Frenchman incorrectly adjudged his opponent's shot to have landed in.
World number 51 Donaldson was 6-3, 3-2 down in his Monte Carlo Masters first-round match against Albert Ramos-Vinolas when the incident took place.
Ramos-Vinolas' serve appeared to land out but umpire Gabas maintained the ball had landed inside the service box.
In a heated exchange that lasted almost a minute, Donaldson screamed "there's a mark right here!" in the face of Gabas, prompting a court supervisor to intervene.
Video replays later showed Donaldson was correct but Hawk-Eye technology is unavailable at the ATP event.
The 21-year-old went on to lose the first-round match in straight sets before leaving the court without shaking Gabas' hand.
Donaldson later offered Gabas a curt apology, saying: "I'm sorry I hurt your feelings, I apologise."
Gabas was forced to have surgery in February last year after being struck in the eye by a wild shot from Denis Shapovalov.
Shapovalov was fined $7,000 for the incident in which Gabas sustained a fractured eye socket.
"I remember hitting the ball," a regretful Shapovalov later explained, "and I didn't even realise where it went and then I see the official bending down holding his eye. I was in complete shock and regret right away. I kind of blacked out for the next ten minutes."