"I don't know how anyone is awake right now" was Naomi Osaka's response as the new Australian Open champion struggled to stay awake with the enormity of her Melbourne success yet to sink in.

Osaka was crowned champion and the WTA's new number one following Saturday's 7-6 (7-2) 5-7 6-4 triumph over Petra Kvitova in Melbourne.

The Japanese star became the first woman to win back-to-back grand slams since Serena Williams claimed the 2014 US Open followed by the Australian Open, French Open and Wimbledon in 2015.

Osaka also became the first woman since Jennifer Capriati in 2001 to follow up her debut slam win by claiming the next one.

However, the 21-year-old appeared ready for bed during her post-match news conference at Melbourne Park, which did not get underway until 12:30am local time on Sunday.

Asked to compare the feeling of winning the Australian Open compared to the US Open, where her maiden slam title was overshadowed by Serena Williams' meltdown amid the American's infamous clash with the chair umpire, Osaka told reporters:

"I'm just so tired. I don't know how anyone is awake right now."

"Maybe the next day I'll think about it more. But for me, I still feel very shocked. Like, I felt like the match wasn't completely done, but it was done, you know?"

"It's one of those moments where you're fighting so hard. When it's finally over, you're still in the state of, like, competitiveness."

Osaka appeared to be cruising to consecutive slam trophies after winning a first-set tie-break and taking a 5-3 lead in the second.

However, Osaka squandered three championship points as two-time Wimbledon champion Kvitova forced a third and deciding set.

Osaka left the Rod Laver Arena court in tears at the end of the second set before returning composed and focused en route to the Daphne Akhurst Memorial Cup, which saw her become the first female or male Asian number one.

Reflecting on her emotions heading into the third set with the final in the balance, Osaka said: "I just thought to myself that this is my second time playing a final. I can't really act entitled."

"To be playing against one of the best players in the world, to lose a set, suddenly think that I'm so much better than her that that isn't a possibility..."

"I wanted to enjoy my time here. Last year I lost in the fourth round. Now this year I was in the final, so I wanted to be happy about that. Just basically have no regrets about today."

And she finally had her magical moment.