Angelique Kerber and Sara Errani have lost in the Qatar Open

World No 2 Angelique Kerber has crashed out in the second round of the Qatar Open to China's Zheng Saisai.

Sara Errani, the 16th seed, has also been sent packing after losing in straight sets to Hungary's Timea Babos.

But Kerber's loss caused the biggest shock, little over a month since she won her maiden Grand Slam at the Australian Open.

Kerber lost 7-5 6-1 to Saisai, the world No 73 who was beaten by Johanna Konta at the Australian Open, in her first individual tournament outing since victory in Melbourne.

Errani followed her out of the tournament after a 6-4 6-1 loss to Babos but Petra Kvitova, Roberta Vinci and Agnieszka Radwanska were among the top seeds to keep their Qatar Open campaign alive on Wednesday.