Mensik reached his maiden tour-level semi-final after firing 10 aces to dispatch the Russian in 98 minutes. The victory over the World No. 5 marked Mensik's first Top 5 win in his career. He is the youngest player to accomplish that feat since Carlos Alcaraz of Spain toppled Stefanos Tsitsipas of Greece at the U.S. Open in 2021.
Mensik will continue his quest for glory against France's Gael Monfils, who posted a 6-2, 6-4 win over countryman and third-seeded Ugo Humbert. With Thursday's win, the 37-year-old Monfils became the oldest semi-finalist in tournament history.
Also on Thursday, Australian Alexei Popyrin posted a 6-4, 6-4 win over fourth-seeded Alexander Bublik of Kazakhstan. Popyrin will face Russian Karen Khachanov, who led 3-0 over Emil Ruusuvuori before the Finland native retired from the match due to injury.
Rio Open
Second-seeded Cameron Norrie of Great Britain cruised into the quarter-finals in Rio de Janeiro with a 6-1, 6-1 victory over Tomas Barrios Vera of Chile.
Norrie converted six of 10 break-point opportunities, compared to one of three for his opponent. Norrie also dominated first serve points at 16 of 21 (76 percent) to six of 21 (29 percent) for Barrios Vera.
Fifth seed Sebastian Baez beat fellow Argentine Facundo Diaz Acosta 7-6 (1), 6-3, and sixth seed Dusan Lajovic upset fellow Serbian Laslo Djere, the sixth seed, 6-2, 7-5.
Other winners were Brazil's Joao Fonseca and Thiago Monteiro, both wild-card entrants, Brazil's Thiago Seyboth Wild and qualifier Mariano Navone of Argentina. Fonseca, 17, is through to his first career quarter-final.
Mifel Tennis Open
Australia's Jordan Thompson avoided an upset, rallying from a first-set bagel to beat the United States' Alex Michelsen 0-6, 7-6 (1), 7-5 in the quarter-finals in Los Cabos, Mexico.
Thompson, the eighth seed, had more aces, 6-2, and winners, 20-8. He converted all three of his break-point opportunities, while Michelsen was five of 16.
No. 4 Casper Ruud of Norway handled Nuno Borges of Portugal, 6-3, 6-2, meanwhile there were straight-set wins for both Stefanos Tsitsipas of Greece and top seed Alexander Zverev.
