Second-seeded Caroline Garcia of France moved into the Tianjin Open quarter-finals after defeating Chinese qualifier Zhang Yuxuan 6-3 6-4 on Thursday.
The 16th-ranked Garcia will play sixth-seeded Petra Martic of Croatia for a semi-final berth on Friday.
Third-seeded Elise Mertens of Belgium also advanced by defeating Slovakian qualifier Jana Cepelova 6-2 6-3.
Mertens' serve was broken both times she offered Cepelova an opportunity, but Mertens had the upper hand by breaking serve six times in the match.
Mertens will play fifth-seeded Hsieh Su-Wei of Taiwan in the quarters.
Timea Bacsinszky of Switzerland reached the quarter-finals with a 1-6 6-3 7-5 win over Japanese qualifier Misaki Doi.
Ranked No.329, Bacsinszky is on the comeback trail following a long layoff with a right leg injury. This marks her first successive wins since Wimbledon last year.
Bacsinszky will take on fourth-seeded Aryna Sabalenka of Belarus in the quarterfinals.
The 101st-ranked Katie Boulter of Britain advanced her cause to earn a top-100 ranking for the first time by securing a quarter-final berth.
Boulter defeated Barbora Krejcikova of the Czech Republic 6-3 1-6 6-3 to arrange a quarter-final against top-seeded Karolina Pliskova.
Pliskova and Sabalenka are in the hunt to secure one of the remaining three spots in the eight-player WTA Finals that begins in Singapore on October 21.
