German second seed Angelique Kerber is out of the China Open after losing in three sets to China’s Zhang Shuai.
The Wimbledon champion won just seven points in the third set as she lost 6-1 2-6 6-0 to the world number 45.
Japan’s Naomi Osaka, the US Open champion, will play Zhang in the quarter-finals after beating Germany’s Julia Gorges 6-1 6-2.
Meanwhile, Petra Kvitova, who lost in the first round in China, booked her place at the season-ending WTA Finals.
It came after Czech Republic’s Katerina Siniakova beat Dutch world number 11 Kiki Bertens 6-4 6-3 in Beijing, ensuring Kvitova will finish the season inside the world’s top eight and qualify for this month’s finals.
Denmark’s world number two Caroline Wozniacki, who has also qualified for the WTA Finals, beat Estonia’s Anett Kontaveit 7-5 6-4.