OSAKA, Japan -- Former champion Samantha Stosur reached the Japan Open semifinals, beating Misaki Doi of Japan 6-1, 3-6, 6-3 on Friday.

Awaiting the third-seeded Stosur on Saturday is American teenager Madison Keys, who advanced to her first WTA semifinals with a 6-3, 6-1 victory over China's Zheng Jie.

In the other semi, Canada's Eugenie Bouchard faces Japan's Kurumi Nara.

Stosur, who won the title in 2009, raced ahead 5-0 in the opening set, but Doi rallied to rouse the home crowd and take the second set. The two exchanged service breaks in the third before Stosur held on to win.

Bouchard beat Barbora Zahlavova-Strycova of the Czech Republic 2-6, 6-4, 6-1 in their quarterfinal. Nara defeated Polona Hercog of Slovenia 7-6 (4), 2-6, 6-1.