Angelique Kerber happy with birthday win over Madison Keys

Fifth seed Angelique Kerber has expressed her delight at celebrating her 25th birthday by progressing to the fourth round of the Australian Open.

Kerber overcame 17-year-old American wildcard Madison Keys 6-2 7-5 in 100 minutes on Rod Laver Arena.

"It was a very tough match because Madison is a great young player," said Kerber. "I was just trying to focus point by point and I'm so happy to win on my birthday."

Kerber will face Ekaterina Makarova in round four, after the Russian beat Marion Bartoli 6-7 6-3 6-4.