Second-seeded Caroline Wozniacki of Denmark reached the Pan Pacific Open semifinals with a 6-3, 6-3 win over eighth-seeded Carla Suarez Navarro of Spain on Friday.
Wozniacki was in control from the outset, breaking her opponent three times in the opening set at Ariake Coliseum.
The U.S. Open finalist will face Garbine Muguruza of Spain on Saturday.
Muguruza, despite 10 double faults, defeated Casey Dellacqua of Australia, 3-6, 7-6 (5), 6-3.
Top-seeded Angelique Kerber of Germany overpowered sixth-seeded Dominika Cibulkova 6-3, 6-0 for a third successive win over the Slovak this year.