Fifth seed Angelique Kerber has sailed into the third round of the Australian Open.

The German disposed of Czech Lucie Hradecka in straight sets on Wednesday, completing a 6-3 6-1 victory.

Kerber has had her best year by far on tour, winning titles in Paris and Copenhagen and reaching the Wimbledon semi-finals and the French Open quarter-finals.

She will play the winner of the clash between American Madison Keys and 30th-seeded Austrian Tamira Paszek for a fourth-round berth.

Meanwhile, fourth seed Agnieszka Radwanska was forced to fight back in both sets before moving through her second-round clash with Romanian Irina-Camelia Begu.

Radwanska, who is unbeaten this year after tournament wins in Auckland and Sydney, eventually won 6-3 6-3 in 86 minutes.

Begu surprised the Polish player by breaking serve in the first game then fighting her way back into the match after Radwanska was serving for the first set at 5-1.

The Romanian also produced a comeback in the second set as Radwanska let go of a number of chances.

“I’m very happy to be playing my best tennis at the the start of the year,” Radwanska said.

“It’s always great to win in two sets.”