Fired-up Maria Sharapova marches on

A fired-up Maria Sharapova strained her vocal chords to exhaustion as she fought off a stiff challenge from German Julia Goerges to advance to the fourth round of the Australian Open today.

Pumping her fist and bellowing "c'mon!", the former world number one dug herself out of a first-set hole and survived a late wobble before sealing the match 4-6 6-4 6-4 at Hisense Arena with a thumping serve in a shade under two-and-a-half hours.

"I wasn't really happy with the first set, especially being up a break," said 2008 champion Sharapova, the last former winner left in the draw.

"Most important thing is, I fought for my chances. I stepped it up and started hitting a little bit deeper."

After steadying in the second set, Sharapova appeared to be cruising to the finish line at 4-0, but the 38th-ranked Goerges threw caution to the wind, blasting winners from the baseline.

Unnerved, Sharapova surrendered her serve after being left flat-footed by a searing forehand winner down the line, but she held on grimly to serve out the match and have a chance of raising her second title at Melbourne Park.

Sharapova was unable to defend her 2008 title due to injury and was knocked out of the first round last year by compatriot Maria Kirilenko.

A quarter-final showing at Roland Garros in 2009 has been her best grand slam showing since her Melbourne Park triumph and while the naturally aggressive 23-year-old has shown glimpses of her best, 11 double-faults against Goerges showed her serve remains highly vulnerable.

Her court movement has got better with every match and the Russian was pleased to be reaching peak fitness after managing to chase down much of what her opponent threw at her.

"I didn't feel tired, didn't feel like I was losing the points because I didn't get there."