Sharapova held her nerve to recover from love-30 down in the pivotal ninth game of the deciding set to hold and then break Kvitova to book a berth in her third final in Melbourne.
"I felt like in the third set she always had the advantage. I was always down 15-30, 30-40 on my serve," a relieved Sharapova said.
"I just said to myself: 'You have really got to go for it and hit it and not give her the chance to finish off the points the way she likes to'.
"Maybe that was the key."
The 24-year-old credited her famous competitive spirit for reaching her sixth grand slam final - three years after requiring career-threatening shoulder surgery to her serving arm.
"I love this sport," the Russian said.
"Sometimes even if you are not playing your best tennis, you can find a way to win.
"It's a one-on-one sport - it's between you and your opponent."
Earlier, in an equally high-quality encounter, Azarenka resisted a second-set comeback from the 11th seed before asserting her dominance and nervously serving out her semi-final.
An emotional Azarenka admitted she became jittery while holding three match points for a spot in the final.
The 22-year-old wasted one with a double-fault and a wry smile crossed her face as she missed her first serve on her second match point. But the contest was all over when Clijsters sprayed a return out of court.
"I felt like my hand is about 200kg and my body is about 1000kg and everything is shaking," Azarenka said.
"But that feeling when you finally win is such a relief. It's like 'Oh my God, I cannot believe it's over'.
"I just want to cry."
Azarenka felt powerless to stop Clijsters in the second set. "Kim really took over the second set; there was nothing I could do. I just tried to regroup and keep fighting."
Azarenka will carry an 11-match winning streak into the final after also taking out the Sydney International lead-up event.
With Caroline Wozniacki falling to Clijsters in the quarter-finals, Azarenka or Sharapova will displace the Dane as world No 1 on Monday, as well as collecting the A$2 million winner's cheque tomorrow.
- AAP