Melbourne –

Former Australian Open champion Naomi Osaka fought back from a set down Wednesday to reach the third round of a Grand Slam for the first time since the birth of her daughter in 2023, gaining a "little revenge" for her defeat at the U.S. Open.

The Japanese star, who won in Melbourne in 2019 and 2021, dropped the first set against 20th seed Karolina Muchova before winning 1-6, 6-1, 6-3.

It was her second three-set test in two days after being pushed all the way by Caroline Garcia in the first round.

"Honestly, it took everything," Osaka said when asked how she turned the match around.

"I felt like I left everything I had on the court. I could have done better, but just to be back on these courts.... It really makes my whole year."

The Czech Republic's Muchova was victorious when the pair last met, at the 2024 U.S. Open, and she was out of the blocks quickest, sweeping to the first set in 32 minutes.

Osaka hit back with a double-break before closing out the second set with a rapid service game.

Osaka continued to improve against a dangerous opponent who made the semifinal in Melbourne four years ago.

The former world No. 1 Osaka, on the back of some blistering groundstrokes, struck the first blow in the decider as she broke for a 3-2 lead.

A searing backhand winner down the line saved a break point in the next game and another consolidated her advantage at 4-2.

"It means a lot, she's an incredibly difficult opponent for me to play," Osaka said of Muchova.

"She crushed me in the U.S. Open when I had my best outfit ever," she laughed. "I was so disappointed. I was so mad.

"This was my little revenge."

Up next for Osaka is Switzerland's Belinda Bencic, who returned to the tour late last year after giving birth to her daughter.

Osaka made her own comeback 12 months ago after a maternity break.

"It probably adds extra stuff for you guys. Not necessarily for me," Osaka told reporters.

"I think we're labeled 'moms' of course. I think when you go on the tennis court, you just think of yourself as a tennis player, first of all.

"I haven't caught up with her because I haven't seen her." Tokyo Olympics champion Bencic leads the pair's head-to-head record 3-2 but Osaka won their last meeting in the semifinals of Miami three years ago.

"I know she's an incredibly tough player. She fights a lot," added Osaka, who is looking to win her first title since her 2021 triumph at Melbourne Park.

"I don't want to say I've grown up with her, but we've definitely seen each other on tour. It's really cool that she also had a baby and she came back as well.

"She seems to be doing really good. So yeah, I think it's going to be fun."

The news was not as rosy for other Japanese players on Wednesday.

Yoshihito Nishioka failed to test No. 3 seed Carlos Alcaraz, falling in straight sets by a 0-6, 1-6, 4-6 score line.

Moyuka Uchijima nearly upset Russian teen Mirra Andreeva, but lost in a tight tiebreak in the third set.