Ukraine's Elina Svitolina beat Caroline Wozniacki in straight sets to win her fifth title of the year and condemn the Dane to a sixth final loss in 2017.
Fifth seed Svitolina won 6-4 6-0 at the Rogers Cup to become the first woman to win three events at the elite Premier 5 level in the same year.
The 22-year-old could become world number one if results go her way at next week's Cincinnati Open.
Wozniacki, seeded sixth, has lost all six finals she has played this year.
After her victories in Dubai and Rome, Svitolina's win in Toronto takes her past Wozniacki, Maria Sharapova, Serena Williams and Victoria Azarenka as a three-time winner of Premier 5 titles in the same season.