Osaka threatened to mentally unravel after losing 18 of 22 points from 5-3 and 40-love up on Kvitova's serve in the second set.
"I'm just trying to take maximum from the minimum".
On what's been a wonderful comeback after being the victim of a knife attack two years ago, she added: 'It's hurting a lot today.
Osaka also became the first woman since Jennifer Capriati in 2001 to follow up her debut slam win by claiming the next one. "I don't ever want to waste this opportunity".
While Osaka will become the new women's number one, replacing Romanian Simona Halep, when the world rankings are released on Monday, Kvitova will be a spot behind.
"I think if I didn't regroup after the second set, then I would have looked back on this match and probably cried or something".
"Thank you for sticking with me even when we didn't know if I would able to hold a racquet again", Kvitova told her team, with her voice cracking.
As AAP writer Darren Walton put it, Osaka was "robbed of the spotlight by Williams after her extraordinary meltdown".
"I mean, to me, it doesn't [feel like a quick rise],' she said following her Australian Open title win". So that's why I wasn't yelling as much in the third set.
After receiving her trophy, Osaka said: "Public speaking isn't really my strong side so I just hope I can get through this".
That allowed Kvitova to come back and make a match of it, reeling off five games in a row to take the second set and go up 1-0 in the third. "And now, after winning the Australian Open and becoming world number 1, she is a superstar!" "As I said on the court, I didn't know if I (was) going to hold the racket again".
But there was this, which was no small thing: Kvitova, who will now be ranked No. 2, proved to herself that she can be the player she used to be, and can contend for Grand Slam championships.
With a resilience forged in the strife-torn US Open final, Naomi Osaka clinched her second Grand Slam title at the Australian Open on Saturday, but this time there was no drama that could sour her triumph. I just set up the mind that I really wanted to come back, and I just did everything.
Melbourne Park erupted in thunderous cheers as the Japanese youngster fell to one knee, head bowed, before collecting the trophy from China's Li Na - who lifted the same silverware in 2014 to become the first Asian to win a major.
The pair had never met before and Osaka initially struggled to unlock the lanky left-hander's serve, while Kvitova at times could not handle her opponent's powerful returns.
"I read notes before this but I still forgot the rest of what I was supposed to say", Osaka said with a laugh.