Mensik upset Sinner 7-6(3), 2-6, 6-3 for the biggest win of his career by PIF ATP Ranking. Two years ago, the Czech notched his maiden Top 5 victory against Andrey Rublev<\/a> during his breakout run to the championship match in Doha. On Thursday night, he produced a nerveless deciding set to prevail in his maiden Lexus ATP Head2Head meeting with Sinner and book a semi-final meeting with Arthur Fils<\/a>. <\/p>\n Worthy of a salute \ud83e\udee1<\/p>\n 2024 finalist @mensik_jakub_<\/a> posts his first ever Top 3 triumph @QatarTennis<\/a> | #QatarExxonMobilOpen<\/a> pic.twitter.com\/ZW36RRgFT9<\/a><\/p>\n \u2014 ATP Tour (@atptour) February 19, 2026<\/a> <\/p>\n \u201cI don\u2019t know, to be honest,\u201d said Mensik, when asked how he had closed out his win. \u201cBefore the match I knew about Jannik\u2019s quality. A great guy, a great champion. Already what he has done in his young career, it\u2019s 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, and actually having a winning mindset. <\/p>\n \u201cI served pretty good, even if the conditions were starting to get slower during the night. It was a very tough mental battle. After the second set, when I dropped my energy a little bit, I\u2019m really happy that I came back after the toilet break and from the beginning of the third set, I just started to serve well again. I\u2019m just happy with the performance I showed today.\u201d <\/p>\n Mensik produced a relentless serving performance to sink Sinner. He won 82 per cent (49\/60) of points behind his first delivery, according to Infosys ATP Stats, and he recovered impressively in the third set after a mid-match drop in his level. <\/p>\n The Czech dug himself out of an early hole in the quarter-final clash by escaping 0\/40 and saving four break points overall to hold serve in the third game. With his serve starting to fire, Mensik did not face another break point in the set and won five of the final seven points in the tie-break, clinching the set with a powerful forehand that left Sinner helpless. <\/p>\n Sinner\u2019s reaction to dropping the first set of his debut Doha campaign was emphatic. He quickly levelled the match, reeling off four consecutive games from 2-2, albeit with the help of Mensik. The Czech could not maintain his first-set level from the line and produced three double faults, including two en route to being broken in the sixth game. <\/p>\n Yet there was nothing Sinner could do about Mensik\u2019s big finish. Continuing to go for his shots whenever he had the chance to dictate, the sixth seed broke serve in the opening and closing games of the deciding set to complete a famous two-hour, 12-minute triumph. The Czech, who is chasing his second ATP Tour title of 2026 after winning Auckland in the first week of the year, coolly walked to the net to embrace Sinner after completing the job. <\/p>\n The 2025 Miami champion Mensik is now 4-2 against Top 5 opponents, a tally that includes victories against ATP No. 1 Club members Novak Djokovic<\/a> and Sinner, and he is up three spots to No. 13 in the PIF ATP Live Rankings as a result of his exploits in Doha so far. He will bid to reach the final in the Qatari capital for the second time on Friday, when he faces the 21-year-old Fils. <\/p>\n Having made his return to action earlier this month after playing just two matches in the preceding eight months due to a back injury, Frenchman Fils earned his first tour-level semi-final appearance since last April by overcoming Jiri Lehecka<\/a> 6-3, 6-3. <\/p>\n \u201cI didn’t know that I was going to play that good that fast, for sure,\u201d said Fils in his post-match press conference. \u201cYou don’t know what to expect when you are back from injury since, what, six to eight months. So you don’t really know what to expect. <\/p>\n \u201c[I\u2019m] pretty happy with the way I’m playing now. It’s not my best tennis yet so far, but we’re getting there. I just need to fight every match to play a lot of balls, to play a lot of games, sets, points, to get again ready, and getting better and better.\u201d <\/p>\n \u00a0<\/p>\n<\/a><\/p>\n