World No 1 Angelique Kerber suffered defeat by Russia’s Anastasia Pavlyuchenkova on the first day of the WTA Elite Trophy.
Pavlyuchenkova, beat Kerber 6-3, 3-6, 6-2 in one hour and 54 minutes at the Zhuhai Hengqin International Tennis Centre in southern China.
American Coco Vandeweghe earlier hit her Chinese wild card challenger.
The second start downed China player Peng Shuai 3-6, 6-3, 6-2 in one hour and 55 minutes.
The 25-year-old had previously four tournaments only won one match in her past.
Peng had got off to a good start and holding serve to give her 3-0 lead to securing the break in the second game.
The Elite Trophy,12 players placed nine position and below in world rankings.