US Open champion Naomi Osaka reached back-to-back Grand Slam finals with a hard-fought win over Czech seventh seed Karolina Pliskova at the Australian Open.

The Japanese fourth seed won 6-2 4-6 6-4 and will face Petra Kvitova, another Czech, in Saturday’s showpiece.

Osaka, 22, hit 15 aces and 56 winners in a confident display, BBC reports.

The semi-final was played under the Rod Laver Arena roof as temperatures touched 40C in Melbourne.

Osaka hit another forehand winner to give herself a match point at 40-30, shouting “come on” as she looked up to the sky and tried to compose herself, then hit what she thought was a 111mph ace down the middle.

After it was called out, Osaka challenged and clasped her hands together in hope as she watched the replay – and was left celebrating when Hawkeye showed the ball had clipped the line.

The final will see Osaka and 28-year-old Kvitova, who has reached her first Grand Slam final since being stabbed, battling for the world number one ranking.

The winner will replace Romania’s Simona Halep as her 48-week reign comes to an end.

The defeat ended 26-year-old Pliskova’s hopes of reaching her second Grand Slam final and set up a first all-Czech final against her Fed Cup team-mate.