Doha, Feb 20 : Jakub Mensik caused a major upset in the Qatar Open when the 20-year-old stunned World No. 2 Jannik Sinner in the quarterfinal of the ATP 500 event.

Mensik beat Sinner 7-6(3), 2-6, 6-3 for the biggest win of his career by ATP ranking.

Two years ago, the Czech notched his maiden Top 5 victory against Andrey Rublev during his breakout run to the championship match in Doha.

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 and Sinner, and he is up three spots to No. 13 in the ATP Live Rankings as a result of his exploits in Doha so far, ATP reports.

â??Before the match I knew about Jannikâ??s quality. A great guy, a great champion. Already what he has done in his young career, itâ??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, and actually having a winning mindset," Mensik said.

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.

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 6-3, 6-3.

â??I didn't know that I was going to play that good that fast, for sure. You 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.

â??Iâ??m 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," said Fils in his post-match press conference.

/IANS