Stefanos Tsitsipas was a victim of an early upset at the US Open, losing his second round match against Daniel Altmaier.

Tsitsipas felt revitalised after winning his opener at the US Open, defeating Alexandre Muller 4-6, 6-0, 6-1, 7-6(7-5).

But his success story was short-lived, with Altmaier overcoming 26th seed Tsitsipas 7-6(7-5), 1-6, 4-6, 6-3, 7-5 in round two.

It continued a disappointing season for the former ATP Tour number three, who is currently ranked 28th in the world.

He has, however, managed to claim one title in 2025 so far, emerging victorious in Dubai at the start of March.

Daniel Altmaier and Stefanos Tsitsipas shake hands at the net after their match at the 2025 US OpenPhoto by CHARLY TRIBALLEAU/AFP via Getty ImagesNick Kyrgios has unexpected reaction to Stefanos Tsitsipas exiting the US Open

Tsitsipas’ fellow ATP star Nick Kyrgios withdrew from the US Open, but he has been keeping tabs on the Grand Slam.

Kyrgios praised Daniil Medvedev after his US Open exit, and the Australian has now done something similar with Tsitsipas.

READ MORE: Daniel Altmaier gives his verdict on Stefanos Tsitsipas’ conduct after confrontation at the net following US Open clash

The Greek ace was mocked via an Instagram post shared by ATP WTA memes that read: “The haters said he couldn’t do it.

“The haters said he’d never win a Grand Slam. And they were correct. Honestly great call from the haters.”

Commenting on the post, Kyrgios wrote: “Guy’s made over 30 mill usd. Haters will continue to hate whilst sitting with their hands in their pants.”

How did Stefanos Tsitsipas describe Nick Kyrgios in 2021?

Kyrgios certainly isn’t afraid to speak his mind, and his latest verdict should undoubtedly be warmly welcomed.

Tsitsipas isn’t enjoying the best spell of his career, and it remains to be seen if he can ever return to his top form, but he already boasts a phenomenal CV.

YearTitlesTournaments20251Dubai (Outdoor/Hard)20241ATP Masters 1000 Monte-Carlo (Outdoor/Clay)20231Los Cabos (Outdoor/Hard)20222Mallorca (Outdoor/Grass)
ATP Masters 1000 Monte-Carlo (Outdoor/Clay)20212Lyon (Outdoor/Clay)
ATP Masters 1000 Monte-Carlo (Outdoor/Clay)20201Marseille (Indoor/Hard)20193Nitto ATP Finals (Indoor/Hard)
Estoril (Outdoor/Clay)
Marseille (Indoor/Hard)20181Stockholm (Indoor/Hard)Stefanos Tsitsipas ATP titles

The 27-year-old Greek has won 12 ATP Tour titles, which include success at the 2019 ATP Finals in London.

Tsitsipas has also reached two Grand Slam finals, although lost both to Novak Djokovic at the 2021 French Open and 2023 Australian Open.

Kyrgios certainly knows that feeling, having lost the 2022 Wimbledon final to the legendary Serbian figure.

Day Six: The Championships - Wimbledon 2022Photo by Simon Stacpoole/Offside/Offside via Getty Images

Discussing the Australian back in 2021, Tsitsipas said on the No Challenges Remaining podcast: “Nick, I’ll call him the black sheep of the ATP.

“He likes to do unpredictable stuff. He likes attention, let’s not refute that. And that’s totally normal. There is nothing bad with it.

“He has his own personality which stands out. Some people love it, I have a lot of people that hate it and don’t understand it, and some people that are so much into it.

“I see it as something totally fine. I think our sport needs that, it’s entertainment, it’s fun, something unique, special that not many players have, as long as he’s not disrespectful.

“He might have been a few times, and that’s not cool, but when he’s not and he’s in total respect of the game and does the right thing, I think it’s really fun to watch.”

New NCR!

Stefanos Tsitsipas (@StefTsitsipas) joins to discuss topics including quarantine, growing up on the internet, Nick Kyrgios, Daniil Medvedev, and the muse inspiring his SoundCloud love songs.

Listen:https://t.co/E7MVqOiqjI

— No Challenges Remaining (@NCR_Tennis) January 27, 2021

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The duo certainly know each other well, while their journeys have even included a doubles pairing at Washington in 2019.

Both players are now at intriguing points in their careers on the ATP Tour, with Kyrgios continuing to struggle with fitness and Tsitsipas struggling for form.