Petra Kvitova breezed past defending champion Garbine Muguruza 6-1 6-4 to move into the quarter-finals, while world number one Angelique Kerber battled past Barbora Strycova in the second round of the China Open on Wednesday.
Kvitova, the winner of last week's Wuhan Open title, won three of her four break point opportunities against the second-seeded Spaniard to ease to victory in one hour and 13 minutes and continue her late push for a spot in the WTA finals in Singapore.
The 14th seed will next face eighth-seeded American Madison Keys, who fought back from a 2-5 deficit in the first set to beat Russian Svetlana Kuznetsova 7-6(2) 6-2, in the last eight.
"I think I'm mentally tough right now. I know that my game is there so I know I just need to hit it like I can," Kvitova told reporters.
German Kerber twice failed to close out the match against Strycova before overcoming a late surge from the Czech to win 6-3 7-6(4). Kerber will face Elina Svitolina of Ukraine for a spot in the quarter-finals.
U.S. Open finalist Karolina Pliskova also secured a third-round spot after recovering from losing the first set against Daria Kasatkina of Russia to win 3-6 7-5 7-6 (7).
Pliskova, the fifth seed, will face Britain's Johanna Konta, who beat Hungary's Timea Babos 7-5 6-2 in a rain-affected match.
(Reporting by Nivedita Shankar in Bengaluru)