Brisbane, Australia (Sports Network) - Serena Williams eased into the quarterfinals of the season-opening Brisbane International, while Maria Sharapova was forced to withdraw from the tournament because of a collarbone injury.

Williams, this year's third seed, dominated in a 6-2, 6-2 rout of Frenchwoman Alize Cornet. The American star has won her last 14 matches and will have a day off before playing in the quarterfinals against the winner between Swede Sofia Arvidsson and American Sloane Stephens.

Sharapova had a bye into the second round as the second seed and was set to take on Australian Jarmila Gajdosova on Wednesday, but has been unable to lift her shoulder above her head to serve because of the injury. The Russian star is still hoping to play in the Australian Open later this month.

Gajdosova will still play her second-round match Wednesday against lucky loser Lesia Tsurenko of Ukraine.

A couple of top seeds were upset in second-round play Tuesday, as Sara Errani and Petra Kvitova were each shown early exits.

Slovak veteran Daniela Hantuchova, a finalist at this event last year, rallied past the fifth-seeded Errani with a 4-6, 6-1, 7-5 triumph, while Russian Anastasia Pavlyuchenkova pulled off a 6-4, 7-5 win against the sixth-seeded Kvitova.

Also Tuesday, Kazakh qualifier Ksenia Pervak followed up her first-round upset of eighth-seeded Caroline Wozniacki with a 3-6, 6-2, 7-6 (8-6) win over Poland's Urszula Radwanska.

Top-seeded Victoria Azarenka will be in action for the first time this season on Wednesday with a second-round match against Germany's Sabine Lisicki. Azarenka, beginning preparations to defend her Australian Open crown, had a bye into the second round. She won this event in 2009 and was the runner-up in 2008.

The Sports Network