World number one Victoria Azarenka proved her form and fitness with a crushing victory over France's Alize Cornet in round one of the China Open.
The Belarusian, who having complained of dizzy spells, thrashed Cornet 6-1 6-0.
Second seed Maria Sharapova beat Simona Halep 7-5 7-5 and 10th seed Caroline Wozniacki defeated Chanelle Scheepers.
But fourth seed Petra Kvitova was beaten 6-3 6-2 by Spain's Carla Suarez Navarro in the second round.
Kvitova's defeat by the world number 46 follows a second-round loss to Croatia's Petra Martic in Tokyo.
In the men's event, fourth seed and 2011 runner-up Marin Cilic was stunned by Romanian wildcard Marius Copil.
World number 221 Copil fought back from losing the first set to prevail 3-6 6-6 (7-0) 6-4.