The 25-year-old Pole will face Ukraine's Elina Svitolina for a place in the championship match.
Earlier in the tournament, Świątek defeated Sara Bejlek of the Czech Republic, Viktorija Golubic of Switzerland and Marta Kostyuk of Ukraine.
The Canadian Open is a combined women's and men's hard-court tournament held annually in Toronto and Montreal.
In the men's tournament, Poland’s Hubert Hurkacz was eliminated in the third round by Botic van de Zandschulp of the Netherlands.
Świątek, a former world No. 1, was eliminated in the third round of Wimbledon last month by Alexandra Eala of the Philippines, failing to defend her title in London.
(gs)
Source: PAP