Stefanos Tsitsipas of Greece waves to the crowd following losing to Andrey Rublev of Russia in the first round of the US Open on Tuesday.
CNN  — 

While she may not have been at the top of her game on Tuesday, Osaka is back on her most comfortable surface. She’s reached two quarterfinals this summer in Toronto and Cincinnati, and all three of her career singles titles have been won on hard courts, having also won Indian Wells in 2018.

The No. 8 seed from Greece was beaten by Andrey Rublev, with the Russian advancing 6-4, 6-7(5), 7-6(7), 7-5 after three hours, 54 minutes. But Tsitsipas also made waves when he clashed with chair umpire Damien Dumusois.

During the match, Tsitsipas was hit with a code violation for receiving coaching; among those in Tsitsipas’ box is his dad and coach, Apostolos.

In the fourth set, when he was battling cramps, Tsitsipas at one point was given a time violation for not returning to the court quickly enough during a changeover.

It was then he was heard saying to the chair umpire from France, “You have something against me, I don’t know what – because you’re French, probably. And you’re all weirdos.”

Tsitsipas was asked about his weirdos comment in his post-match press conference.

“The chair umpire was very incorrect in what he was telling me during the match,” Tsitsipas said. “I don’t know what this chair umpire has in specific against my team but he’s been complaining and telling me that my team talks all of the time when I’m out on the court playing. He’s very – I don’t know. I believe he’s not right, because I never hear anything of what my team says from the outside. And there is nothing that I personally believe can help my game or make me play better.

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“My father outside, who usually does the talking, he’s trying to pump me up by saying, you know, ‘Come on.’ Raising my confidence by not coaching but by trying to boost me up. I believe the coach for my opponent does the same thing, which is normal.

“This chair umpire, I don’t know, he has something against me. I don’t know why.”

Tsitsipas reached the Australian Open semifinals earlier this year, defeating Roger Federer en route. He reached the fourth round at the French Open, but he lost in the first round of Wimbledon.

BIRMINGHAM, ENGLAND - JUNE 18: Naomi Osaka of Japan celebrates victory in her first round match against Maria Sakkari of Greece during day two of the Nature Valley Classic at Edgbaston Priory Club on June 18, 2019 in Birmingham, United Kingdom. (Photo by Jordan Mansfield/Getty Images for LTA)
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Meanwhile, Rublev’s hot streak continues. Earlier this month, the 21-year-old dispatched Federer in just over an hour at the Western & Southern Open in the Cincinnati suburb of Mason, Ohio. It was Federer’s quickest defeat in 16 years. Rublev reached the final eight at the US Open in 2017.

Thiem, Khachanov, Bautista Agut also lose

Tsitsipas is not the only seed in the top 10 to lose on Tuesday. Italy’s Thomas Fabbiano upset No 4 seed Dominic Thiem of Austria 6-4, 3-6, 6-3, 6-2, Canada’s Vasek Pospisil shocked No. 9 seed Karen Khachanov of Russia 4-6, 7-5, 7-5, 4-6, 6-3, and Mikhail Kukushkin of Kazakhstan upended No. 10 seed Roberto Bautista Agut of Spain 3-6, 6-1, 6-4, 3-6, 6-3.

Serbia's Novak Djokovic holds the winner's trophy during the presentation after beating Switzerland's Roger Federer during their men's singles final on day thirteen of the 2019 Wimbledon Championships at The All England Lawn Tennis Club in Wimbledon, southwest London, on July 14, 2019. (Photo by Daniel LEAL-OLIVAS / AFP) / RESTRICTED TO EDITORIAL USE        (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images)
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Even Rafael Nadal, who won in straight sets against John Millman on Tuesday, sounded astonished to hear of the upsets.

“That’s tennis,” the No. 2 seed and 18-time major champion said. “That’s all the reaction I can say, no? When you start the tournament, you have difficult opponents in front. You need to go on court and respect every single opponent.

“I went on court today against a tough opponent knowing that I need to play well to win. If you play bad, you can lose. Tsitsipas had a very tough first round. Of course, Karen is a surprise. I think Thiem have been very sick for the last 10 days. I feel very sorry for him. … Roberto was a surprise. Honestly, I’m very sad for him.”