Jakub Mensik stunned Jannik Sinner 7-6 (7-3) 2-6 6-3 to reach the semi-finals of the Qatar Open, where he will face Arthur Fils.

In the first ATP Tour-level meeting between the players, Mensik held his nerve in a deciding set after the world number two threatened a comeback win.

Mensik had to resist plenty of pressure in the opening set, saving four break points in the third game en route to a tie-break, which he saw out after racing into a 4-1 lead.

Things looked ominous when Sinner took control of the second set, holding to love on two occasions then registering back-to-back breaks to take the match the distance, helped by three double faults from his Czech opponent.  

But Mensik found a second wind in the third set, breaking in the first game then doing so again in the ninth, with Sinner failing to lift his forehand over the tape on match point. 

Asked how he saw out the victory, Mensik said: "I don't know, to be honest! Before the match, I knew about Jannik's quality. He's a great guy, a great champion. 

"What he has already done in his young career... it's pretty impressive, so I knew it was going to be a tough one. But even with that thought, I came to the match to win it, with a winning mindset.

"I served pretty well, even if the conditions were starting to get slower during the night. It was a very tough mental battle. I'm just happy with the performance I showed today."

Signal of intent 

What a way for @mensik_jakub_ to clinch his 5th ATP semi-final!@QatarTennis | #QatarExxonMobilOpenpic.twitter.com/CwpBKU7e27

— ATP Tour (@atptour) February 19, 2026

Data Debrief: Mensik claims biggest scalp yet

This was Mensik's first victory over a top-three ranked player, and his fourth over a top-five opponent.

Mensik, who needed two hours and 12 minutes to clinch his victory, is now 4-2 against top-five foes and is chasing his second ATP Tour title of the season, having triumphed in Auckland last month.

Toppling Sinner is no mean feat, and Mensik is the first player from outside the ATP's top 10 to beat the Italian on a hard court since Ben Shelton did so in Shanghai in 2023.