Postpublished at 11:17 Greenwich Mean Time 26 January 2019
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
Twelve months ago, Naomi Osaka was ranked 72 in the world.
She's now the world number one and a two-time Grand Slam champion.
Naomi Osaka 7-6 (7-2) 5-7 6-4 Petra Kvitova
Kvitova saves three championship points to force third set
Osaka becomes world number one after winning back-to-back Grand Slam titles
Amy Lofthouse
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
Twelve months ago, Naomi Osaka was ranked 72 in the world.
She's now the world number one and a two-time Grand Slam champion.
Gigi Salmon
Radio 5 live sports extra tennis commentator at Melbourne Park
Spare a thought for Kvitova. She has achieved so much since returning from that knife attack.
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
Kvitova has her head in her hands, wiping away her tears.
The absolute grit she showed to get back into this match at a set and a break down.
She'll win another Slam. Mark my words.
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
Russell Fuller
BBC tennis correspondent at Melbourne Park
At the age of 21, she has won back-to-back Grand Slams and this time she can rejoice in the moment. This is her moment! She has won it in dramatic style after a fabulous comeback from Kvitova.
She is the first player in 18 years to win a first Grand Slam title and then follow it up by winning her second. What an extraordinarily resilient woman, what an extraordinary player.
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
Osaka gets down on her haunches and covers his eyes with her visor as she cries, just as she did four months ago.
In New York, she was overwhelmed by the situation. This time, they're tears of joy.
Back-to-back Grand Slam titles for Naomi Osaka. What a player.
Kvitova 6-7 (2-7) 7-5 4-6 Osaka
SHE'S DONE IT!
Naomi Osaka is the Australian Open champion!
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
No, that's out!
Big, deep hitting from both players, and it's Osaka who whips her backhand long.
15-40...
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Osaka just misses her first serve...
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
A wayward volley from Petra Kvitova!
Three Championship points to Naomi Osaka.
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Shot!
And now a down the line forehand from Osaka.
30-0.
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Hello!
A big ol' ace starts Naomi Osaka's service game off.
15-0.
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Russell Fuller
BBC tennis correspondent at Melbourne Park
She's had three championship points, she served for the title before, this is her chance again.
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Here we go.
(It's just started raining)
Kvitova 6-7 (2-7) 7-5 4-5 Osaka*
Bam.
Big first serve from Kvitova.
Osaka will once again serve for the match.
*Kvitova 6-7 (2-7) 7-5 3-5 Osaka
Long goes Osaka's return to Kvitova's second serve, before she goes into Osaka's body.
40-15.
*Kvitova 6-7 (2-7) 7-5 3-5 Osaka
Unbelievable backhand from a full-stretch Kvitova and Osaka, in the middle of the baseline, nets her winner.
There's a gentleman in the crowd who genuinely screams in agony.
15-15.
*Kvitova 6-7 (2-7) 7-5 3-5 Osaka
Kvitova attempts a lob as she's overpowered by Osaka - and it doesn't clear the net.
0-15.
*Kvitova 6-7 (2-7) 7-5 3-5 Osaka
Here we go...
#bbctennis
Shego: Petra just needs to play the whole match like she's *0-40 down.
*Kvitova 6-7 (2-7) 7-5 3-5 Osaka
A deep shot from Osaka is called long.
She's got one challenge left, so she risks it - and she was right to! It's landed smack on the baseline.
She holds, thanks to a wayward volley from Kvitova. Once again, Osaka is a game away from the Australian Open title.