Jannik Sinner was handed his second defeat of the 2026 season by Jakub Mensik at the Qatar Open.
After winning his first two matches at the ATP 500 event in Doha, Sinner lost to Mensik in three sets, 7-6, 2-6, 6-3.
The Italian has recorded a fairly indifferent start to the year, by his standards, having kicked off his campaign with a failed title defence at the Australian Open.
Is it time to start worrying about Jannik Sinner yet?
He has not looked himself in 2026…
Sinner was beaten by Novak Djokovic in the semifinals at Melbourne Park, with the Serb denying him the chance to three-peat.
Now, with his defeat to Mensik, one of the 24-year-old’s incredible streaks on the ATP Tour has finally come to an end.
Jannik Sinner’s hard-court streak comes to an end in Doha
Mensik claimed the fourth top-five win of his career against Sinner, in what marked their first clash at a tour-level event.
He also became the first player ranked outside the ATP top 10 to defeat Sinner on a hard court in nearly three years, according to Opta Ace, with the Czech star currently 16th in the world.
The last player to manage the feat was Ben Shelton, who did so back in 2023 at the Shanghai Masters.
Shelton, 20th in the world at the time, came back from a set down to defeat Sinner that day, before being knocked out by compatriot Sebastian Korda in the next round.
Since then, Sinner has been dominant against players outside the top ten, and he lost just 12 matches overall across 2024 and 2025.
Jannik Sinner’s worst losses on clay and grass since 2023
Though he remained undefeated on hard court during that time period, Sinner suffered a few losses to players ranked outside the top ten on clay and grass.
At the 2024 Monte Carlo Masters, Sinner was beaten by Stefanos Tsitsipas on the dirt, losing in three sets.
In 2025, weeks before his maiden Wimbledon triumph, Sinner was beaten by Alexander Bublik on the grass courts of Halle.
Late last year, Tallon Griekspoor did advance past Sinner at the Shanghai Masters on hard court, but it was via a walkover.
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