After an even first set, Osaka won the tiebreak to nudge ahead. She was on the brink of victory in the second set, but Kvitova saved three match points and won an absorbing stanza.
Despite that body blow, Osaka steadied herself, and after an early break in the decider, she was strong on serve and clinched the title.
This win for the 21-year-old made it back-to-back Grand Slam successes, as she won her maiden major title at the U.S. Open in 2018. It also put her top of the WTA rankings.
Awesome Osaka On Top of the World
In the opening exchanges, it was easy to see why both Osaka and Kvitova had made it to the final, as they produced tennis of the highest quality.
Both players were rock-solid, and when their opponent did conjure break points, the other delivered in clutch moments across the net.
Per Eleanor Crooks of the Press Association, Osaka dug herself out of a hole in the seventh game:
At 6-5 down, Kvitova saved a couple of set points, and it felt like she had recaptured some momentum going into the tiebreak.
But Osaka played the best tennis at this crucial point in the contest. She found a stunning backhand return to take control, then two sizzling winners to move into a more commanding position.
Here's a look at the return in question:
An error by Kvitova helped Osaka take the breaker and move to within touching distance of the title.
The competition's Twitter account noted the size of the challenge that Kvitova faced:
Tennis journalist Reem Abulleil provided the numbers to show just how well the Japanese played in the opening set:
At the start of the second stanza, Kvitova played better, as she rediscovered a fizz in her forehand, moving 2-0 ahead with the first break of the match.
Osaka responded exceptionally. She broke back at the first opportunity, and after an emphatic hold of serve, she broke Kvitova to love, moving 3-2 in front.
There was still work for her to do, though, and Kvitova ended a run of four straight games for her opponent with a solid hold, making sure Osaka had to work for the title.
The Czech then did brilliantly to save three match points and make her rival serve it out.
For the first time, Osaka was a little tight, and some loose shots gave Kvitova a route back into the contest, as she broke serve and then moved 6-5 ahead. The youngster played a terrible game when serving to stay in the set and double-faulted to give Kvitova unlikely parity.
Tennis journalist Tumaini Carayol commented on the change in mood from Osaka with Kvitova grabbing momentum going into the decider:
The manner in which Osaka lost the second set made her recovery all the more remarkable, as she took the initiative in the third with an early break. Kvitova continued to make life difficult, too, as she saved three break points to ensure she didn't fall 5-2 behind.
It meant Osaka was again presented with a chance to serve for the match. This time, she made no mistake, moving 40-0 up and sealing her second Grand Slam with a huge serve.