Date fells Hantuchova

The former world number four won 2-6, 6-0, 4-0 after her Slovakian opponent retired with a shoulder injury.

Second seed Vera Zvonareva overpowered Italian Sara Errani 6-3, 6-3 to underline her title credentials at the $2 million tournament. 

Top seed Caroline Wozniacki of Denmark crushed Hungarian Greta Arn 6-1, 6-3 but fourth seed Samantha Stosur of Australia was eliminated 7-5, 6-3 by Germany's Julia Goerges and Russian Svetlana Kuznetsova also lost.

The 10th seed went down 6-3, 7-5 to German Andrea Petkovic in another upset but 11th-seeded Frenchwoman Marion Bartoli avoided a potential banana skin by crushing Serb Ana Ivanovic 6-2, 6-1 in a lop-sided encounter.

Del Potro stumbles
Former US Open champion Juan Martin del Potro fell at the first hurdle on his return from injury when he lost 7-6, 6-4 to Belgian Olivier Rochus in the opening round of the Thailand Open.