Fourth seed Agnieszka Radwanska has expressed her delight at defeating Ana Ivanovic to reach her fourth Australian Open quarter-final.

The Pole, who will face Li Na in the last eight, beat the former world number one 6-2 6-4 on Sunday evening.

"I'm very happy I could play my best tennis today," said Radwanska.

"Ana played more aggressively in the second set and was volleying well, but in the important moments I was focused and I'm glad I could close it out in two sets."

Radwanska has now won 13 consecutive matches.