Sharapova, Serena through

Sharapova, who won the last of her three Grand Slam titles in Melbourne four years ago, reached the last 16 having conceded just five games in three matches after 6-0 6-1 victories in the first two rounds.

Kerber, the 30th seed, offered a little more resistance to the aggressive Russian than her predecessors with a service break after a 15 minute game at 2-0 down in the second set.

Sharapova, however, simply upped the decibel level in her shrieks and battered her opponent into submission with her ferocious groundstrokes in 87 minutes.

"I felt like I was aggressive enough," she said. "In the first set, I didn't give her a chance to do what she likes. In the second set, it became a bit more of a battle. But I felt like I stepped it up when I had to here and there."

Fourth seed Sharapova will face another German in Sabine Lisicki in the fourth round with a potential showdown against five-times champion Serena Williams looming in the quarter-finals.

The 14th-seeded Lisicki bounced back from dropping the first set to beat 18th seed Svetlana Kuznetsova 2-6 6-4 6-2.

Serena Williams raced into the last 16 of the Australian Open with a powerhouse display that left Hungary's Greta Arn stunned after a 6-1 6-1 drubbing on Rod Laver Arena.

The 13-times Grand Slam champion landed only half of her first serves but still cantered to victory in 59 minutes.

Arn produced same late resistance to prise a couple of break points from the American when trailing 4-1 in the second set, but surrendered the match meekly with a double-fault on the first of three match points.

Williams faces world number 56 Ekaterina Makarova in the fourth round after the Russian upset countryman and seventh seed Vera Zvonareva in straight sets, 7-6(7) 6-1.

Second seed Petra Kvitova blasted into the fourth round when Russian Maria Kirilenko retired with a leg injury after the first game of the second set of their third round match, having lost the first 6-0.

Kvitova had torn through the first set in 34 minutes and then broke Kirilenko in the first game of the second before the 29th seeded Russian walked to the net and shook hands with the Czech.

Kvitova started slowly with the first game of the match taking 10 minutes before she broke Kirilenko and then ruthlessly exposed Kirilenko's hampered movement from the baseline.

Kirilenko took a timeout after going 5-0 down to have her upper left leg heavily strapped and, while she returned, Kvitova picked up where she left off.

Kvitova will next play former French Open champion Ana Ivanovic in the last 16, after the Serb beat America's Vania King 6-3 6-4.

Ninth seed Marion Bartoli was also sent crashing out of the tournament, comprehensively over-powered by former semi-finalist Zheng Jie 6-3 6-3.

The Chinese player will face Sara Errani in the fourth round after the Italian ousted Sam Stosur's conqueror Sorana Cirstea 6-7(6) 6-0 6-2, the Romanian needing treatment for a back injury in the course of the loss.