In his debut at the Qatar Open, Sinner failed to set up the anticipated classic final against Carlos Alcaraz. The Italian player was defeated by 20-year-old talent Mensik, who is known for creating upsets, holding a 4-2 record against top 5 opponents. Two years ago, the Czech player secured his first top 5 victory against Andrey Rublev on his way to the final in Doha.

Mensik celebrates a winning point during his quarterfinal match against Sinner at the Qatar Open, on Center Court in Doha, Qatar on 19/2. *Reuters*

To overcome Sinner, Mensik delivered an exceptional serving performance. He won 82% of points on his first serve (49/60), achieved a 71% first serve percentage, and showed impressive recovery in the third set after a mid-match dip.

Mensik navigated early danger, saving four break points, including recovering from 0-40 down in the third game. As his serve became more effective, he faced no further break points in the set. Mensik won the tie-break 7-3, sealing the final point with a powerful forehand that left Sinner stranded.

Sinner responded strongly after losing the opening set. He quickly leveled the match, winning four consecutive games from 2-2, partly due to a lapse from Mensik. The Czech player could not maintain his first set serving form and committed three double faults, two of which occurred in the sixth game, leading to a break.

However, Sinner could not prevent Mensik's late surge. The number 6 seed continued to attack at every opportunity, converting break points in both the first and final games of the deciding set to complete his victory in two hours 12 minutes.

Sinner returns a ball during his quarterfinal match at the Qatar Open, on Center Court in Doha, Qatar on 18/2. *Reuters*

Advancing to the semifinals, the 2025 Miami Open champion will climb at least three spots to number 13 in the ATP rankings. He will aim for his second Doha final when he faces 21-year-old Arthur Fils.

Returning to competition earlier this month after eight months sidelined with a back injury, having played only two matches, French player Fils secured his first ATP Tour semifinal berth since april last year by defeating Jiri Lehecka 6-3, 6-3. In the other semifinal, Alcaraz will face defending champion Andrey Rublev.

Vy Anh