Garbine Muguruza outclassed Caroline Garcia to reach the Pan Pacific Open semi-finals and Angelique Kerber beat Karolina Pliskova in a tussle between two former world number ones.
Muguruza has looked ominous in her first tournament since moving to the top of the rankings and the top seed was too good for Garcia, winning 6-2 6-4 in Tokyo on Friday.
The powerful Wimbledon champion lost only four points on serve in the opening set, breaking twice to put one foot in the last four.
Garcia racked up too many errors and a clinical Muguruza took advantage, unleashing blistering winners as she claimed another two breaks in the second set to prevail.
Kerber has endured a year to forget, but the two-time grand slam champion may be turning the corner on the evidence of a 7-6 (7-5) 7-5 triumph over Pliskova.
The seventh seed from Germany looked far sprightlier than she has been for much of 2017 and was rewarded with a first win over a top-10 rival this season.
Kerber's backhand proved to be a potent weapon and after edging a first-set tie-break, she claimed the only break of the match to reach the last four.
Anastasia Pavlyuchenkova will be Kerber's semi-final opponent after the Russian saw off Barbora Strycova 5-7 6-3 6-1.
Muguruza will take on defending champion Caroline Wozniacki, who was 3-1 up in the third set when Dominika Cibulkova retired due to a right thigh injury.