Top-seeded Sam Stosur of Australia moved into the Japan Open semifinals with a 6-2, 6-4 victory over Jamie Hampton of the United States on Friday.
Stosur, the 2011 U.S. Open champion, broke her unseeded opponent's serve seven times in the quarterfinal while never facing a break point herself.
Stosur, ranked ninth in the world, will meet Kai-chen Chang of Taiwan on Saturday, after the unseeded Chang ousted eighth-seeded Laura Robson of Britain 6-4, 3-6, 7-6 (4).
Also, unseeded local favorite Misaki Doi advanced to her first WTA semifinal by defeating seventh-seeded Chanelle Scheepers of South Africa, 2-6, 6-1, 6-3.
Doi will take on Heather Watson of Britain in the semis. Watson bested Pauline Parmentier of France 7-5, 6-3.