Daniil Medvedev was heard blasting the chair umpire during his match with Tallon Griekspoor after receiving a code violation for unsportsmanlike conduct at the Dubai Tennis Championships.

Medvedev had reached the quarter-final of the ATP 500 event after beating Jan-Lennard Struff and Giovanni Mpetshi Perricard in the last-32 and last-16, respectively.

The Russian entered the tournament as the No.1 seed but struggled at times against Griekspoor, who survived four match points in the second set to take the match to a decider.

But it was during a row with the umpire where the biggest flashpoint came, with the 2021 US Open winner accusing the man in the middle of being “soft”.

After receiving the violation, Medvedev could be heard screaming: “For what? for what?” The umpire replied with: “For what you said to me.”

The tennis star then asked what he said, with the umpire adding: “You know what you said.” Medvedev responded with: “Ok, so you’re like this, very soft. If you have a problem, I’ll make sure. Now I go to toilet.”

It’s not yet known exactly what Medvedev said to have received the violation, but before his trip to the restroom, the microphones appeared to capture him claiming it was for saying the umpire “had double standards against Russians”.

Unsurprisingly, the umpire didn’t take well to the accusation, with the microphones capturing his response. He said: “Don’t say something like this. Daniil, I’m very fair! I treat you all exactly the same”.

With valuable ranking points on offer, Medvedev would’ve hoped to have gone all the way and taken the title.

It didn’t prove to be the case though, with Griekspoor taking the biggest win of his career in dramatic fashion after defending four match points to win 2-6 7-6 7-5 .

The Dutch ace kept his cool in a sweltering Dubai to confirm a first ATP Tour semi-final. He said afterwards: “I would like to celebrate, but there’s another match waiting tomorrow. Super happy with this win.

“Had to fight off a couple match points in the 2nd set. Daniil is an unbelievable player and competitor. He’s been at the top of the rankings for so many years. Very pleased with this win.”

It’s another bump in the road for Medvedev, who has struggled in recent months. Recognising his poor form, Medvedev had said earlier this month: “I would even say Andy [Murray], at least for the moment, is not comparable to me, because he won so many tournaments, Masters and all those titles.

“And I would say that maybe I like someone like Stan [Wawrinka], who won his first (Grand Slam) when he was 29.

“And this is kind of more inspiring, because he was beaten by those guys from time to time, and he was like, ‘okay, but I’m going to do it’. And that’s what I want to do as well. As I said, lately my level has been a bit lower than I expected, but I know what I’m capable of.”

Griekspoor will now take on Stefanos Tsitsipas or Matteo Berrettini in the semi-final.