German star Angelique Kerber and French Open runner-up Sara Errani advanced, while Aussie favorite Sam Stosur and former No. 1 Caroline Wozniacki suffered first-round upsets at the $1 million Brisbane International, a hardcourt Australian Open tune-up.

The fourth-seeded left-handed Kerber held off Georgian Anna Tatishvili 6-2, 4-6, 6-2, while a fifth-seeded Errani, of Italy, drubbed Russian qualifier Olga Puchkova at Queensland Tennis Centre.

Errani's second-round opponent on Tuesday will be last year's Brisbane runner- up Daniela Hantuchova.

Meanwhile, Swede Sofia Arvidsson knocked out the seventh-seeded former U.S. Open champion Stosur 7-6 (7-4), 7-5 and Russian qualifier Ksenia Pervak toppled the eighth-seeded Danish Wozniacki 2-6, 6-3, 7-6 (7-1). Stosur was a Brisbane finalist back in 2005.

Also, rising American Sloane Stephens bested Slovak Dominika Cibulkova 6-2, 6-3.

Additional wins came for German Sabine Lisicki, France's Alize Cornet and Puerto Rican qualifier Monica Puig. Lisicki's next opponent will be world No. 1 Victoria Azarenka, while Cornet is rewarded with a Tuesday encounter against former No. 1 and reigning Wimbledon, U.S. Open, Olympic and Tour Championships champion Serena Williams, this week's third seed. Azarenka was the Brisbane titlist in 2009 and runner-up in 2008.