MELBOURNE - Japanese tennis star Naomi Osaka secured the women's singles championship at the Australian Open on Saturday, beating America's Jennifer Brady, 6-4, 6-3.

It is the fourth Grand Slam title for Osaka, and her second in Australia after also winning in 2019.

"It feels really incredible for me. I didn't play my last Grand Slam in front of fans so just to have this energy it really means a lot. Thank you so much for coming," Osaka said.

The Japanese was lucky to find herself on the finals at all after creeping through a fourth round match with Garbine Muguruza, in which she miraculously saved two match points.

Meanwhile, Brady reached the final despite being one of over 70 players forced to undergo a two-week hard quarantine at the beginning of the tournament.

"They did everything to make it as comfortable as possible," Brady said. "I was able to do everything I could in the room and I appreciate everything they did for me when I was there."

Despite being the firm underdog in the match, the American put up an impressive fight. Particularly in the first set where she snatched a break back from Osaka and came within reach of edging ahead.

The American squandered a crucial break point in the ninth game, which would have seen her serving for the set. In the end Osaka clung on, with a lucky forehand in the back corner getting her out of trouble.

From there Osaka lifted, winning a total of six straight games to claim the first set and give her a comfortable 4-0 lead in the second.

Brady gave herself a chance, gaining a break in the fifth game and holding serve to take two games back, however despite holding serve again, Osaka's dominant arm carried her home to a fourth Grand Slam title.

"She's such an inspiration to us all and what she's doing for the game is amazing and getting the sport out there," Brady said.

"I hope young girls at home are watching and are inspired by what she is doing."