Australian Open champion Madison Keys, seeded sixth, beat fellow American Caty McNally 2-6, 6-3, 6-3 and will next meet Karolina Muchova, a 6-7 (2/7), 6-2, 6-3 winner over Belinda Bencic.Fifth-seeded American Amanda Anisimova,

Former world No. 11 Anastasija Sevastova admitted she "did not even think" about beating Jessica Pegula after falling behind early, before also hinting at retiring in the next couple of weeks.

Jessica Pegula, the two-time defending champion at the National Bank Open, was upset 3-6, 6-4, 6-1 by Anastasija Sevastova, while Naomi Osaka cruised into the fourth round.