MELBOURNE: Second seed Angelique Kerber received a gift ride into the Australian Open fourth round for her 31st birthday on Friday when she overpowered local wildcard Kimberly Birrell 6-1, 6-0.

The German Wimbledon champion swept world number 240 Birrell aside in just 58 minutes to set up a last 16 clash with unseeded American Danielle Collins.

Kerber, a winner at Melbourne Park in 2016, said she was used to celebrating her birthday on the road at the season-opening Grand Slam.

"I think it's the 12th time in a row," she said. "I'm getting older but I have the best time here and I'll never forget my birthdays here in Australia."

Kerber reached the semi-finals last year but lost to Simona Halep in a tight three-setter.

She is on course for a quarter-final clash with fifth seeded American Sloane Stephens if results go as expected.

The crowd on Rod Laver Area cheered wildly when Birrell, who ousted Croat 29th seed Donna Vekic on her way to the third round, took a point off Kerber's first service game.

But that was about as good as it got for the young Australian as the German three-time Grand Slam winner broke her in the next game.

Birthday girl Kerber was all business, offering no chances to Birrell as she wrapped up the first set in 27 minutes.

She opened the second set with another break and continued her demolition job.

Birrell survived three match points, one when Kerber double faulted, but bowed to the inevitable on the fourth.

Kerber's next opponent Collins is another relative novice at Grand Slam level, though at 35 in the world she has a much higher ranking than Birrell.

The 25-year-old American is on her best run at a major after all five of her previous Slam appearances ended in first-round exits.

Kerber annihilated her 6-1, 6-1 in their only previous meeting at Eastbourne last year.