Kazakhstan's Zarina Diyas books quarter-final spot in Zhengzhou

Diyas sealed a 6-2 6-4 victory over the Japanese player in Zhengzhou to set up a last-eight clash with Shuai.

Number six seed Kurumi Nara of Japan was knocked out however, after she retired from her match with South Korea's Jang Su-jeong trailing 7-5 4-0.

But there were victories for third seed Duan Ying-Ying and fifth seed Zheng Saisai - both of China - after they recorded wins against Austria's Arina Rodionova and Sabina Sharipova of Uzbekistan, respectively, to progress to the quarter-finals.