Wuhan champion Aryna Sabalenka fell in the second round of the China Open on Tuesday.
Sabalenka roared back into form last week by successfully defending her Wuhan Open title but was unable to keep the run going in Beijing, losing 6-4 7-6 (5) to Russian Daria Kasatkina.
Top seed Ashleigh Barty was a comfortable 6-4 6-2 winner against Yulia Putintseva, and fourth seed Naomi Osaka was in ruthless form, beating Andrea Petkovic 6-2 6-0.
Barty next faces China's Zheng Saisai, who comprehensively defeated 13th seed Sloane Stephens 6-3 6-1, while 10th seed Angelique Kerber was knocked out 6-4 6-2 by Polona Hercog.
Defending champion Caroline Wozniacki had no problem advancing, beating Christina McHale 6-4 6-0, and there were also wins for Petra Kvitova, Sofia Kenin and Alison Riske.