Two-time champion Victoria Azarenka remained in ominous form Monday to surge into the Australian Open quarter-finals, as Chinese qualifier Zhang Shuai's amazing Grand Slam run stayed alive. Former world number one Azarenka proved too strong for Czech Barbora Strycova on Rod Laver Arena, storming through 6-2, 6-4 to set up a last-eight clash with Angelique Kerber, who beat fellow German Annika Beck 6-4, 6-0.