While the top level of tennis is usually kept very clean and professional, many interesting things often happen on the ATP Challenger Tour, and one of those happened recently.
Verbal clashes on the court rarely happen in tennis because most players are very good at internalizing thoughts. Some of them simply stop caring at the moment, and it's all out.
Fans got to see some of those in recent years. There is a famous instance from the Canadian Open between Maria Sakkari and Danielle Collins. Even Daniil Medvedev had his moment on the ATP Challenger Tour when he was defaulted from a match.
The most recent ATP Challenger instance happened in a match between Radu Albot and Mark Lajal, which was played in Lille. Albot won the opening set rather comfortably 6-2 and was up a break in the second set.
He was up a break in the second set and was looking forward to ending it in a few games. 4-3 was the score for the Moldovan, but unfortunately for him, he was facing a break point in that game.
He would never get the score to 5-3 because his forehand went wide, and his opponent, Lajal, was very enthusiastic about breaking back. Excessively so, according to Albot, who let out his frustration quite a bit after a point.
"Shut the f*ck up, you piece of sh*t."
As far as the video shows, there wasn't any code violation as the umpire was busily announcing the score, and Lajal was too distracted to really notice, either.
In any case, Albot eventually won the match, though he needed three sets, so the second set didn't finish off that well. He still got the win on the court, winning the match 6-2, 6-7(5), 6-3, but claiming some negative reputation as a result of his actions.