Petra Kvitova blazed her way into her first Australian Open final with victory over Danielle Collins under the roof on Rod Laver Arena.

With temperatures soaring towards 40C in Melbourne, the tournament's new extreme heat policy came into play and the roof was closed with the score at 4-4 in the first set.

Kvitova, who has struggled in the past in hot conditions, found the cooler temperatures much more to her liking and powered to a 7-6 (2) 6-0 victory in an hour and 34 minutes.

This is the Czech's first grand slam final outside of the two Wimbledon titles she won in 2011 and 2014, and she said: "It means everything.

"That's why I really work very hard to be in the finals of tournaments. Finally I could make it deep in this major and I will enjoy the final whatever happens. I'm really very, very happy."

Asked about the closing of the roof, Kvitova said: "The first set was very tight, I was pretty nervous. I think I was happier than the fans that the roof closed. I like playing indoors. It was kind of warm. If it was open I was still going to fight so it doesn't really matter."

Danielle Collins impressive run came to an end

Kvitova had gone from being distinctly under the radar to the title favourite in a couple of days so, as well as being a physical examination, this was a test of how well the Czech could keep her mental cool.

Collins' run has been one of the stories of the tournament and the 25-year-old, who had never previously won a grand slam match, is a confident character who was never likely to be overawed by the occasion.

She showed just that early on as she broke the Kvitova serve to lead 3-2, but the eighth seed also brings a fierce intensity to the court and there were several of her famous screams of 'pojd'(Czech for 'come on') as she broke back immediately.

Collins looked unhappy about the decision to shut the roof, perhaps knowing that, as a Florida native, the heat could have given her a crucial advantage.

Still there was nothing to choose between them until the tie-break, when Kvitova stepped up to a new level and left a frustrated Collins in her wake.

The American had a brief exchange with umpire Carlos Ramos, the central figure in last year's US Open final drama, over his decision to replay a point after an over-rule but by that point was already 5-1 behind.

Kvitova was now well and truly in her groove and Collins found herself helpless in the second set as the eighth seed blasted 13 winners in six games.

Naomi Osaka could win her second Grand Slam in a row

Kvitova's opponent in the final will be Naomi Osaka, who kept her hopes of winning back-to-back grand slam titles alive by dispatching Serena Williams' conqueror Karolina Pliskova.

Osaka produced a brutal display of power hitting under the roof, striking 56 winners in a 6-2 4-6 6-4 victory.

The 21-year-old's achievement makes her the first women to back up a first slam title by making the final of the next major tournament since Jennifer Capriati in 2001.

As well as the title, the world number one ranking will also be on the line on Saturday, with Kvitova and Osaka both looking to get there for the first time.

Capriati followed her maiden title here 18 years ago by winning the French Open and, if Osaka can maintain the form she showed in this match, then there is absolutely no reason why she cannot emulate that.

Having survived tough battles against the unconventional pair of Hsieh Su-wei and Anastasija Sevastova earlier in the tournament, Osaka certainly looked more comfortable taking on a fellow ball-basher.

And bash the ball she did, repeatedly into the corners, off both forehand and backhand, to win the first set.

Osaka had won her previous 58 matches after winning the first set but - following her remarkable comeback to beat Williams - Pliskova would have known that no cause was impossible.

Osaka broke serve again at the start of the second set but then gave it straight back with a poor game and slowly the momentum began to shift, the two women trading fiercer and fiercer blows.

Osaka produced some fine play to hold off her opponent at 3-4 but two games later Pliskova broke to love to take the match to a decider.

The 26-year-old, who reached her only slam final at the US Open in 2016, looked to continue her momentum at the start of the decider but Osaka saved three break points before playing a tremendous return game to move 2-1 ahead.

Pliskova had one chance to get back on level terms in the eighth game but Osaka served an ace, and then another one - given by HawkEye - to clinch the victory.

Osaka said: "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."