Doha, Qatar – In a stunning upset at the Qatar ExxonMobil Open, 20-year-old Jakub Mensik defeated world No. 2 Jannik Sinner in the quarter-finals on Thursday, securing his place in the semi-finals. The Czech Republic native overcame Sinner 7-6 (7-3), 2-6, 6-3 in a match lasting over two hours, marking the biggest win of his career by Professional International Tennis Federation (PIF) ATP Ranking according to the ATP Tour.
The victory halts Sinner’s impressive 22-match winning streak, with his only previous defeat in that run coming against Novak Djokovic in the semi-finals of the Australian Open last month. Mensik, currently ranked No. 16, demonstrated remarkable composure and serving prowess to dismantle the Italian’s momentum and advance to the final four.
Mensik’s performance was particularly notable given Sinner’s dominant form in 2025, where he reached 10 finals, claiming titles at both the Australian Open and Wimbledon. However, the young Czech proved too strong on Thursday, delivering a clinical performance that disrupted Sinner’s rhythm and ultimately led to the upset. Tennis Infinity reported that Sinner had opportunities early in the match, but Mensik saved all four break points.
“Of course before the match I knew about Jannik’s qualities,” Mensik said following the win. “He’s a great guy. A great champion. I knew it was gonna be a tough one… I’m really happy I came back after the toilet break. From the beginning of the 3rd set I just started to serve well again.”
Mensik’s Path to the Semi-Finals
This isn’t Mensik’s first notable result in Doha. Two years prior, he notched a victory against Andrey Rublev during a successful run to the championship match at the Qatar ExxonMobil Open. This latest win builds on that pedigree, solidifying his position as a rising star in the ATP Tour. The ATP Tour highlighted Mensik’s nerveless performance in the deciding set as crucial to his victory.
The match saw a fluctuating dynamic, with Sinner taking the second set 6-2 after Mensik claimed the first in a tiebreak. However, Mensik regained control in the third, securing key breaks to close out the match and secure his semi-final berth. He produced a relentless serving performance to sink Sinner.
Semi-Final Matchups Confirmed
Mensik will now face unseeded Frenchman Arthur Fils in the semi-finals. Fils advanced after defeating Mensik’s compatriot, Jiri Lehecka, in straight sets 6-3, 6-3. Fils recently added Goran Ivanisevic to his team and is looking to reach his fourth ATP final and his second title of 2026, having won the Auckland Open last month.
In the other semi-final, world No. 1 Carlos Alcaraz will face defending champion Andrey Rublev. Both players secured their spots in the final four after winning their respective quarter-final ties. Alcaraz battled past Karen Khachanov, while Rublev continued his title defense with a strong performance.
What’s Next?
The semi-final matches promise exciting competition as Mensik and Fils, along with Alcaraz and Rublev, vie for a place in the Qatar ExxonMobil Open final. Mensik’s victory over Sinner has undoubtedly established him as a player to watch, and his performance in the semi-finals will be closely scrutinized. The tournament continues to deliver compelling action, showcasing the depth of talent within the ATP Tour.
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