It was the 19-year-old Gauff’s first loss since the quarterfinals in Montreal, a span that included titles in Cincinnati and at Flushing Meadows.
The Polish player made just four unforced errors in the first set, keeping consistent pressure on Gauff’s serve, and made a decisive break at 3-1 to ease through the set in 40 minutes.
Swiatek maintained her vice-like grip on the match, breaking Gauff at the start of the second set to lead 2-0.
A medical timeout to have Gauff’s right shoulder assessed didn’t break Swiatek’s momentum as she closed it out to extend her head-to-head record against her rival to 8-1.
“I’m really happy with my performance,” Swiatek said. “It feels like I can play freely again, so I’m really happy. It’s been a while since I felt that way. So, I’ll remember for the rest of my career that even though tougher times may come, in your mind, you can always overcome that. And with hard work, you can achieve it.”
In his first appearance in Shanghai since winning the title in 2019, Medvedev was ruthless as he overpowered the 98th-ranked Garin in 92 minutes, including breaking the Chilean player five times.
The second-seeded Russian will next play 26th-seeded Sebastian Korda.