Petra Kvitova and Naomi Osaka will do battle for the Australian Open title and the world number one ranking at Melbourne Park on Saturday.

Kvitova reached her first grand slam final outside of Wimbledon with a 7-6 (2) 6-0 victory over surprise package Danielle Collins before US Open champion Osaka made it back-to-back finals by beating Karolina Pliskova 6-2 4-6 6-4.

For Kvitova, the achievement is the latest step in her inspiring recovery from the stabbing by an intruder at her home in December 2016 that nearly ended her career.

The damage to the fingers on her playing hand was so severe that doctors feared she may not play professionally again, while the mental scars were just as deep.

The 28-year-old, who won her second title at Wimbledon in 2014, said: "I'm still not really believing that I'm in the final. I didn't know even if I was going to play tennis again.

"It wasn't really a nice time to be dealing with everything. It wasn't only physically, but mentally it was very tough, as well.

"It took me really a while to believe in the people around me again, and especially men, for sure. I wasn't confident to be alone somewhere.

"It was a lot of work with the hand, a lot of recovery, treatment. I think the sport life helped me a lot with that. I just set up the mind that I really wanted to come back, and I just did everything.

"Those three months were very, very tough. I found out lately that my doctor wasn't really happy with my hand during the second month, because the scars were very, very tight and hard, and I couldn't really do anything with that.

"Luckily he didn't tell me during that period. It's been a long journey.

"I'm really happy to be back (in a final) again. I think not very many people believe that I can do that again, to stand on the court and play tennis and play at this level. It was just really a few of them, I think.

"I'm very happy to have those few around me. Definitely it feels great. Hopefully for them as well, for my family and for everybody who was there when I needed it."

Kvitova's clash with Collins, who had never won a slam match before arriving here, began in temperatures of nearly 40C before the roof was shut at 4-4 in the first set in accordance with the tournament's new extreme heat policy.

As the temperature came down, Kvitova's level rose, and the second set was an exhibition of power tennis from one of the cleanest ball-strikers in the game.

While Kvitova welcomed the cover, Collins, who hails from Florida, would rather have played on in the heat.

She said: "I think they need to start the match the way it's going to finish.

"Indoor tennis is a different game. It certainly had its effect. But it is what it is, and she played really great tennis. I think that should probably be the focus of the conversation."

Collins will rise to a new career-high ranking of 23, and she added: "I think last year I did a really great job of showing people in Miami and Indian Wells, San Jose, plenty of tournaments throughout the year, that I can play at this level.

"I think I have justified that. Maybe some people thought I was a one-hit wonder, it was a fluke. Clearly none of this has been a fluke."

Osaka continues to look every inch the real deal as the next dominant star of women's tennis and she extended her record of consecutive slam victories to 11, becoming the first woman since Jennifer Capriati in 2001 to follow up a maiden title by reaching the next slam final.

Osaka hit 56 winners but just as impressive was the mental strength she showed to recover from losing the second set and survive tight moments in the third.

Pliskova admitted her remarkable comeback against Serena Williams on Wednesday may have taken its toll, saying: "It's not only that the match yesterday was tough, but also it was emotionally tough, too.

"I was missing maybe a little bit of power today. But she played an unbelievable match, maybe the best in her life. I don't think she can repeat a match like this."

Osaka said in response: "I don't necessarily think I played the best I've ever played.

"For me, what I take away from this is that I never gave up, and that's something that I'm really proud of myself for.

"There were moments in the match where I thought, 'This is getting really close'. I just thought I wouldn't forgive myself if I had a little dip or a moment of accepting defeat."