Greek tennis star Stefanos Tsitsipas’ choice words for German opponent Daniel Altmaier were caught on a hot mic after he beat him at the U.S. Open.
After Altmaier defeated the Greek star in five sets in the second round of the games, Tsitsipas threw shade at him for using the rare underhand serve and indicated he tried to strike him with a ball, according to The Guardian.
“Next time, don’t wonder why I hit you, OK? No, I’m just saying if you serve underarm,” Tsitsipas said as the pair shook hands following the match.
Altmaier responded by patting him on the shoulder.
Stefanos Tsitsipas had some words with Dan Altmaier after losing to him at U.S. Open:
He’s complaining about Dan hitting an underarm serve during the 4th set.
Frosty. 🥶
— The Tennis Letter (@TheTennisLetter) August 29, 2025
As the German star started to move away from him, Tsitsipas walked closer, repeating, “If you serve underarm.”
An underhand serve is legal in tennis, but is considered a controversial tactic since it can catch an opponent off guard.
Altmaier ended the spat by waving him off and going to shake hands with the umpires. After the confrontation, Altmaier expressed sympathy for his opponent.
“I know that sometimes in the heat of the moment you can say stuff which you don’t normally would like to say,” Altmaier said, according to Ben Rothenberg’s Substack, Bounces. “Even if I would have lost, I would not enter discussions because it’s just like heat of the moment. You need to cool down.”
Daniel Altmaier was caught on a hot mic criticizing his opponent for using an underarm serve. Mike Stobe/Getty Images
“Let’s see if he reacts to it or he sticks to his opinion,” he added.
This isn’t the first time Tsitsipas has gotten in a tiff with another player.
In a 2018 Miami Open match against Russian star Daniil Medvedev, Tsitsipas cursed at him for taking a bathroom break during the match despite him also taking one.
“He said, ‘F—ing Russian.’ You think this is normal?” Medvedev asked the umpire.
The umpire sided with the Russian star, agreeing that Tsitsipas initiated the heated exchange.
This spat between Tsitsipas and Altmaier comes a day after another altercation at the U.S. Open. After American star Taylor Townsend secured a win over Latvian tennis player Jelena Ostapenko, Ostapenko allegedly told Townsend, who is Black, that she had “no class” and “no education,” which users on social media decried as racist.
American star Taylor Townsend said Jelena Ostapenko told her she had “no class” and “no education” during a heated exchange after a match. Clive Brunskill/Clive Brunskill/Getty Images
“[Ostapenko] told me I have no class, no education, and to see what happens when we get outside the U.S.,” Townsend told ESPN.
Townsend, however, did not take the remarks as racist.
“I didn’t take it in that way, but also, you know, that has been a stigma in our community of being ‘not educated’ and all of the things, when it’s the furthest thing from the truth,” she said.
Ostapenko responded to the social media criticism in a now-expired series of Instagram story posts.
“Wow how many messages I received that I am a racist,” she wrote, according to ESPN. “I was NEVER racist in my life and I respect all nations of people in the world, for me it doesn’t matter where you come from.”