16th seed Sharapova was on the back foot for much of the first set against Petkovic who continued with the form that had seen her dispatch world number one Caroline Wozniacki in the fourth round.

After losing that set the Russian immediately broke Petkovic at the start of the second and started to show the type of play that took her to number one back in 2008, producing punishing power off both wings and pouncing on  the Petkovic serve at every opportunity.

The errors were now being forced off 21st seed Petkovic' racquet and Sharapova raced ahead to take 11 straight games.

Petkovic managed to break the pattern at 0-5 down in the third to take the next two games but an undeterred Maria pushed on to win in 2 hours and 7 minutes and was clearly delighted with reaching her first final in over seven months.

"I feel like I'm finding my form," said Sharapova.

"I really felt like with many matches and staying healthy that I would feel better and my (fitness) would start coming back to me and my tennis as well.

"I feel that that's playing out really well."

Sharapova goes on to play Victoria Azarenka of Belarus who convincingly defeated third seed Vera Zvonareva of Russia in a one-sided affair, 6-0 6-3.

21-year-old is expecting a tough match against Sharapova.

"She is playing well, she is a tough opponent, no matter when or where, I am looking forward to it," said Azarenka.

"I know how she plays, she knows how I play so it will be a real battle. I haven't to let her dictate the play, the way she likes."