CNN
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US tennis player Frances Tiafoe has apologized for his profanity-laden outburst directed at an umpire after a defeat at the Shanghai Masters.

The world No. 7 lost 5-7 7-5 7-6 (5) across three hours to unseeded Russian Roman Safiullin in the third round on Tuesday, but he appeared upset when he was given a time violation on a first serve in the final set tie-break with the scores level at 5-5.

“No, no, no, no, I tossed the ball up … I was ready to serve. Dude, that’s the rule,” Tiafoe could be heard saying towards chair umpire Jimmy Pinoargote, arguing that he had thrown the ball in the air for a serve.

In response, Pinoargote said: “I’m not buying it, it’s the second serve,” before also announcing it was Tiafoe’s second serve on the microphone.

Tiafoe would go on to lose the point and the match. After the players shook hands at the net, the 26-year-old directed his anger towards Pinoargote, aiming a series of expletives at the umpire while Safiullin tried to celebrate his win. Meanwhile, some members of the crowd could be heard laughing.

After the match, Tiafoe took to social media to apologize for his behavior.

“I really apologize for the way I acted,” the two-time US Open semifinalist wrote on Instagram. “That is not who I am and not how I want to treat people.

“I let my frustration in the heat of the moment get the best of me and I’m extremely disappointed with how I handled the situation.

“That’s not acceptable behavior and I want to apologize to the umpire, the tournament and the fans.”

According to ATP Tour regulations, players can receive fines of up to $60,000 for verbally abusing officials at Masters 1000 tournaments. CNN has contacted the ATP for comment.