Both players hit 20 winners, but Medvedev had nine unforced errors while Sinner committed 19. Medvedev never faced break point and won 30 of his 37 first-service points (81.1 percent).
Borna Coric of Croatia upset a second straight seeded foe to make the semifinals. After beating No. 2 seed Stefanos Tsitsipas of Greece in the previous round, Coric outlasted Polish fifth seed Hubert Hurkacz 6-4, 6-7 (2), 7-6 (5).
Canada's Denis Shapovalov beat Great Britain's Daniel Evans 6-3, 6-3 and will meet Coric in the semis. Medvedev will face Bulgarian Grigor Dimitrov, who topped Marcos Giron 6-3, 4-6, 6-4.
Swiss Indoors Basel
World No. 1 Carlos Alcaraz beat fifth seed and Spanish countryman Pablo Carreno Busta 6-3, 6-4 to advance to the semifinals in Switzerland.
Alcaraz saved four of five break points while Carreno Busta stayed in the match by saving nine of 12. Next, Alcaraz will face Canadian Felix Auger-Aliassime, who dispatched Kazakhstan's Alexander Bublik 6-2, 6-3.
The other semifinal will pit sixth seed Roberto Bautista Agut of Spain and Denmark's Holger Rune. Bautista Agut got past Switzerland's Stan Wawrinka 7-5, 7-6 (5), and Rune defeated France's Arthur Rinderknech 7-6 (0), 6-2.
