Poland's Agnieszka Radwanska has set up a quarter-final clash with defending Australian Open champion Victoria Azarenka.
The fifth seed booked her place in the last eight for the fourth consecutive year at Melbourne Park with a clinical straight sets victory over unseeded Spaniard Garbine Muguruza.
Second seed Azarenka beat 13th seed American Sloane Stephens in straight sets in her fourth-round match.
Azarenka is the only one of the top 3 seeds still alive after number 3 Maria Sharapova was beaten by number 20 Dominika Cibulkova yesterday to follow Serena Williams out of the first grand slam of the year.
