Victoria Azarenka remains on course to win a third consecutive Australian Open singles title.
The world number two, who is yet to drop a set in this year's Melbourne Grand Slam, needed just 91 minutes to see off America's Sloane Stephens 6-3 6-2 in round four.
Azarenka, who also knocked Stephens out of this competition 12 months ago, won all nine of her service games, saving two break points in the process.
The Belarusian returned brilliantly as well, winning 49% of receiving points, including three of 14 break points.
Azarenka is now the only former Australian Open winner left in the women's draw, after 2008 champion Maria Sharapova suffered a three-set defeat to Dominika Cibulkova earlier on day eight.
