Former champion Maria Sharapova battled to a straight-set win over Swiss Belinda Bencic to progress to the quarter-finals of the Australian Open.
Sharapova, seeded fifth, was erratic but served 21 aces to seal a 7-5 7-5 win after two hours and six minutes.
The Russian will next play either top seed Serena Williams or compatriot Margarita Gasparyan in the last eight.
Sharapova, who made seven double faults and 46 unforced errors, said she expected to next play Williams.
The 28-year-old, who was beaten by world number one Williams in last year's final, said: "It was a great final last year, I came close in the second set but not close enough.