Svetlana Kuznetsova held off Japanese teenager Naomi Osaka 2-6 6-4 7-6 (3) to reach the Tianjin Open semi-finals on Friday.
The second-seeded Russian is trying to clinch one of the last remaining spots for the WTA Finals in Singapore this month. It would be her first appearance in the finals since 2009.
Kuznetsova will play Alison Riske of the United States in the semi-finals after Riske defeated China's Han Xinyun 6-3 6-3.
The other semifinal will feature Danka Kovinic of Montenegro and Peng Shuai of China.
Kovinic beat Olympic gold medallist Monica Puig 6-4 6-3 and Peng advanced when top-seeded Agnieszka Radwanska withdrew with a right thigh injury on Thursday.