Melbourne - World number five Maria Sharapova battled past petite Lauren Davis and into the Australian Open fourth round on Friday as she edges closer to another showdown with arch-rival Serena Williams.
The Russian fifth seed needed two hours, 14 minutes to finally dismantle the hard-working 103rd-ranked American 6-1, 6-7 (5/7), 6-0 with the roof closed on Rod Laver Arena on a wet Melbourne day.
Sharapova's 600th career win sets her up with a tough test next up against 12th seed Belinda Bencic, after the dangerous Swiss teen beat Ukraine's Kateryna Bondarenko.
"In a Grand Slam environment, third round, against an opponent you have not played before and is fired up," Sharapova said, in explaining the second-set wobble.
"I was quite happy I was able to step it up in the third set."
If Sharapova gets through her next match, she faces a potential quarter-final with defending champion Williams.
Williams, who plays later on Friday, has been a huge weight around Sharapova's neck throughout her career, with the Russian unable to beat her since 2004.
The dismal record was extended at Melbourne Park last year when the 21-time Grand Slam champion swept past Sharapova in the final.
Davis, just 1.57m tall, had never been beyond the third round in four previous attempts at the season-opening Grand Slam, but she tried hard to fix that with a dogged second-set performance.
Sharapova, a full foot taller than the 22-year-old, had been in scintillating form so far, dropping just seven games in her opening two matches, and eased herself into the match.
It went with serve until the fourth game when Davis fired a backhand long to give the Russian her first break point.
With the pressure on, the pint-sized American couldn't cope with Sharapova's return serve and sent a wild forehand over the baseline to go 3-1 behind.
A winner here in 2008 and a three-time runner-up, the seasoned Sharapova, sweat dripping, held to love and then comfortably broke again.
The steely-eyed Russian was in no mood to give an inch and she served for the set in just 26 minutes.
She continued to pressure the Davis serve and got the break she was after in the third game of the second set.
But her concentration waned and Davis got her first break point of the match, with Sharapova's backhand into the net levelling it at 2-2.
Buoyed, the American stunned the fifth seed by breaking her again in the sixth game on a double fault.
Another break for the Russian hauled her back into the set and it went with serve to a tense tiebreak, which included an epic 27-shot rally. Davis finally won the set when Sharapova sent a forehand wide.
The Russian went for a toilet break to compose herself and came back refreshed, holding serve and breaking to go 2-0 in front before another break in the fourth game put her on the way to victory as Davis faded.
Earlier, the rapidly improving Bencic, who won two titles in 2015, beat Bondarenko 4-6, 6-2, 6-4.
The Swiss, a product of the tennis school run Martina Hingis' mother Melanie Molitor, finished 2015 at a career-high ranking of 14 after a breakthrough season that also included beating Williams at Toronto.