Osaka's superstar status in the U.S. was solidified when she beat Williams in the U.S. Open women's singles finals in September. On the other hand, the dominant left-handed 28-year old Czech player Kvitová is looking for a great comeback since her previous two Grand Slam titles at Wimbledon in 2011 and 2014. Fighting is in Kvitova's DNA and the Czech fired herself up.
Kvitova can console herself with a career-best performance at Melbourne Park, where she did not drop a set on her way to the final.
The Japanese beat Petra Kvitova 7-6 (2) 5-7 6-4 in Melbourne on Saturday.
Moments after winning what will be remembered as one of the greatest slugfests in Grand Slam history, Naomi Osaka stood at center court, shoulder-to-shoulder with Australian Open runner-up Petra Kvitova, and allowed the slightest satisfied smile to slowly lift her cheeks.
To top it off, she's the first ever Asian world No. 1.
"This is insane. I can not believe I just played the final of a grand slam again", she said.
That ugly encounter had left Osaka crying during the acceptance speeches, when fans were booing Carlos Ramos, who had been called a "liar" and a "thief" by Williams. When Kvitova sailed a backhand wide moments later, ceding a set for the first time all tournament, Osaka pumped her fist and screamed, "Come on!"
This time, Osaka cried with joy and smiled as she became the youngest woman to win back-to-back majors since Martina Hingis in 1998 and the youngest number one since Caroline Wozniacki in 2010.
Osaka's victory Down Under, and accompanying post-match presentation in which both players were handed generous plaudits, was all very different to the win over Serena Williams in NY back in September.
And the tie was nearly wrapped up inside 90 minutes as the 21-year-old earned three Championship points on Kvitova's serve in the ninth game.
'Who knows. I think women's tennis is very open, ' said the Czech, who will rise to world No. 2 when the latest WTA rankings are released on Monday.
Osaka was reluctant to say how she felt compared to Flushing Meadows but believed she and Kvitova were fairly supported in Melbourne.
Supporters in a packed Tokyo bar had a rollercoaster ride watching the action from the Australian Open final as their heroine Osaka contrived to give up three Championship points in the second set. She then squealed in agony as Kvitova broke her again to take the second set on a double fault.
Osaka had won 59 straight matches after taking the first set before Saturday's final and showed why as her serves grew bigger and the winners flowed from her racket in the second.
For Kvitova it was the end of an unlikely dream that has seen her come back so admirably from a horrific knife attack just over two years ago, but she could be proud of the way she battled throughout. Slammed a ball. Tugged at her visor's pink brim.
But Osaka steadied herself after a trip to the locker room before the third set.