Heather Watson moved into the Mexican Open quarter-finals, while teenager Leylah Fernandez continued her run on Wednesday.
Watson, the British seventh seed at the WTA International event, was too good for Kateryna Bondarenko 7-6 (7-2) 6-2.
Zhu Lin was the other seed to advance, getting past Katie Boulter 7-6 (7-2) 7-5 in one hour, 48 minutes.
Another seed fell in Nao Hibino, who was crushed by Canadian 17-year-old Fernandez 6-3 6-0 in just over an hour.
Renata Zarazua, Tamara Zidansek, Anastasia Potapova, Christina McHale and Wang Xiyu also moved into the last eight.