Second seed Wang Qiang made hard work of sealing her place in the quarter-finals of the WTA Biyuan Zhengzhou Women's Tennis Open, but Peng Shuai had no such trouble in her homeland on Wednesday.

Wang lost the first set, but dug deep to see off Valentini Grammatikopoulou 4-6 7-5 6-2 and set up an all-Chinese encounter with Liu Fangzhou.

World number 68 Wang was broken four times by unseeded outsider Grammatikopoulou from Greece before taking charge in the final set to advance.

Top seed Peng took just an hour and 17 minutes to march into the last eight, seeing off Riko Sawayanagi 6-1 6-4. Shiho Akita or Zarina Diyas will be Peng's next opponent. 

Nao Hibino and Liu also reached the quarter-finals with victories over Eri Hozumi and Yang Zhaoxuan respectively.