Jakub Mensik knocked out world number two in the quarter-finals of the Qatar Open to prevent Jannik Sinner from reaching another final.
The sixth seed from the Czech Republic took advantage in the first set and despite Sinner’s equalizer, the 20-year-old Mencic won the decider 7-6 (7-3) 2-6 6-3.
It ended Sinner’s run of 22 wins in 23 matches, with his only defeat coming against Novak Djokovic in the Australian Open semifinals last month.
The 24-year-old Italian reached 10 finals in 2025, winning the Australian Open and Wimbledon titles, but was upset by world number 16 Mencic in his first match in Doha on Thursday.
He will now face unseeded Frenchman Arthur Fils, who defeated Mencic’s compatriot Jiri Lehecka 6-3 6-3 to earn a fourth ATP final in 2026, having won the Auckland Open last month for the second time in his career.
World No. 1 Carlos Alcaraz will face defending champion Andrei Rublev in the other semifinal, with both men having won their last eight matches.
