Christina McHale continued her defence of the Japan Women's Open title on Friday as Elise Mertens and Yulia Putintseva both suffered quarter-final defeats.

McHale beat third seed Mertens 6-4 6-1 to set up a semi-final meeting with Zarina Diyas, who came from a set down to win an all-Kazakh meeting with eighth seed Putintseva 4-6 6-1 6-3.

There will be home interest in the semi-finals after qualifier Miyu Kato overcame Aleksandra Krunic in straight sets, while Jana Fett's fairytale also run continues.

Fett had already beaten Jana Cepelova in Tokyo, and she added Wang Qiang to her list of conquests with a 6-3 4-6 6-3 triumph – setting up a last-four meeting with Kato.