MELBOURNE, Australia - Like the 21-year-old she is, Naomi Osaka stepped into Rod Laver Arena for the Australian Open final with a cell phone in her right hand and music in both ears.

The headphones she wore carried the swirling brass, bouncing beat and boastful lyrics of Jay Rock's Win, the same pre-match song Osaka listened to throughout the tournament - and at last year's US Open, too.

"You might wanna keep score," the rapper says. "I win, win, win, win."

Right now, that's how Osaka is performing at tennis' most important events. Her championship at Melbourne Park, via a 7-6 (2), 5-7, 6-4 victory over Petra Kvitova on Saturday night, earned her a second straight Grand Slam trophy.

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, three years after becoming the first Asian to win a major at Roland Garros.

Later Osaka told a media conference of her hunger to quickly add to her major tally.

"The way the tennis world is, there's always the next tournament, the next Slam, and we all just want to keep training hard and winning more. So I'm not really sure if I'm satisfied," said Osaka, who was born in Osaka, Japan and moved to Long Island, New York at age 3.

Just a year ago, Osaka was ranked 72nd.

She had lost by the third round in seven of her eight appearances at Grand Slam tournaments. The lone exception was a fourth-round run at the Australian Open in January 2018.

Now, she is the first woman with back-to-back major championships since Serena Williams - the player Osaka beat in the US Open final last September - captured four in a row from 2014 to 2015.

The Melbourne triumph sees Osaka ascend to No 1 in the WTA rankings for the first time, making her the youngest player to hold top spot since Caroline Wozniacki was 20 in 2010.

Her gutsy performance against Kvitova also confirms her status as the leading light of tennis' new generation.

"Well, after winning the US Open, Naomi Osaka became a star. And now, after winning the Australian Open and becoming world number one, she is a superstar! Congrats Champ," 18-time Grand Slam winner Martina Navratilova tweeted.

Osaka doesn't think the term "overnight success" applies to her, however.

"I mean, to me, it doesn't. I guess looking from the outside, from your guys' view, it does," she said.

"For me, every practice and every match that I've played, it feels like the year is short and long at the same time. But I'm aware of all the work that I put in. I know all the sacrifices that every player does to stay at this level. I mean, in my opinion, it didn't feel fast. It felt kind of long."

Her growth as a competitor has been so swift, though.

She won four three-setters in Melbourne and beat a trio of top-10 opponents.

Then there was the way Osaka pulled herself together after failing to convert three championship points at 5-3 in the second set against Kvitova, much as she ignored all the chaos surrounding the final against Williams at Flushing Meadows, where the American's beef with the umpire overshadowed her major breakthrough.

"As a whole, this tournament was very eye-opening for me," Osaka said in Melbourne. "I had a lot of matches that were very tough and I was behind in some of them. I think it showed me that I could win matches from behind, just on willpower alone."

Positives for Petra

Kvitova could console herself with a career-best performance at Melbourne Park, where she did not drop a set on her way to the final.

It was her first Grand Slam decider since a burglar slashed her racket hand in a 2016 knife attack and the Czech has shown she is again a contender at the majors.

"Thank you for sticking with me even when we didn't know if I would able to hold a racket again," Kvitova told her team, with her voice cracking.

"It's crazy. I can hardly believe that I just played in a Grand Slam final again."

Associated Press