Two-time champion Victoria Azarenka, unseeded in Melbourne, is into the fourth round.
Victoria Azarenka continued her Australian Open run with a hard-fought win over Barbora Zahlavova Strycova on Saturday.
Unseeded Belarusian Azarenka, whose foot injury ruined her 2014 and cut it short, progressed to the last 16 with a 6-4 6-4 win on Margaret Court Arena.
The two-time champion has already eliminated Sloane Stephens and Caroline Wozniacki at the year's first grand slam.
She added Czech 25th seed Zahlavova Strycova to that list after one hour 46 minutes on court.
It was far from Azarenka's best, as she hit 12 winners and 32 unforced errors to set up a clash with last year's runner-up Dominika Cibulkova.
Zahlavova Strycova started the better of the two, winning the first seven points of the contest.
But she gave up the next eight, seeing Azarenka hold from 0-40 down and then break for a 2-1 lead.
Zahlavova Strycova levelled the contest in the sixth game before both players got more comfortable on serve.
However, Azarenka secured what proved to be the decisive break in the ninth game " Zahlavova Strycova sending a forehand long to fall 5-4 behind.
Azarenka needed three set points to finally seal the set when her opponent pushed a backhand long.
Despite hitting just one winner to go with 13 unforced errors, Azarenka took the first set.
Azarenka improved early in the second and broke in the opening game on her way to a 3-0 lead.
That may have been four, but Zahlavova Strycova got one of the breaks back to trail 3-1.
A pair of double faults proved costly for Azarenka in the sixth game as the set was levelled at 3-3.
Azarenka broke once more in the next game as Zahlavova Strycova reached for a backhand and sent it long on break point.
Again, Azarenka failed to consolidate " and missing an overhead was particularly costly.
But she broke serve again in the ninth game as, after a crafty point, Zahlavova Strycova's cross-court forehand went wide.
A lengthy 10th game was highlighted by 17-shot point, which Azarenka somehow won when Zahlavova Strycova sent a simple volley well wide.
It set up match point, and Azarenka converted thanks to a 39th unforced error from her opponent.