The 24-year-old booked her place in the semi-finals of the year's opening Grand Slam by knocking out the defending champion in a three-set clash that lasted exactly two hours at Rod Laver Arena.
"The best quarter-final for sure," Radwanska beamed in a courtside interview. "I have played a couple of quarter-finals before and I said to myself one day I need to take one step forward and make the semi-final and final. I'm so, so happy that I did it finally.
"It was always hard. I have lost so many times against her before and I knew she was a very great player, very consistent so I just knew that I had to play my best tennis.
"Play aggressive and go for every shot that I could. That was what I was trying to do and it worked today."
Radwanska will play 20th seed Dominika Cibulkova for a place in the final.