The 20-year-old Pole, ranked world No. 8 by the Women's Tennis Association (WTA), defeated Estonia's Anett Kontaveit 6-3, 4-6, 6-3 in their encounter on Saturday.
Świątek is now to face Olympic gold medalist Belinda Bencic of Switzerland.
Meanwhile, Poland’s Hubert Hurkacz crashed out of the US Open men's singles on Thursday after losing to Italy's Andreas Seppi, 6-2, 4-6, 4-6, 6-7, in the second round.
The 2021 US Open runs until September 12.
(tf)
Source: PAP