MELBOURNE, Australia >> Naomi Osaka’s second-round match at the Australian Open could not possibly have started in a worse way. All of 21 minutes in, she sailed a forehand service return well long and, just like that, trailed 5-0.

Osaka strode to the sideline for the changeover, plopped herself down and draped a white towel over her head, blocking out all sights and leaving her with just her thoughts. She stayed like that throughout the break between games, even manoeuvering a water bottle under that towel to take a drink.

This was not a match against some unknown opponent, someone Osaka knew for sure she could beat. It was against 20th-seeded Karolina Muchova, the runner-up at the 2023 French Open and a three-time semifinalist at other majors, including at Melbourne Park in 2021.

Muchova also defeated Osaka in their two most recent matchups. None of that mattered as Osaka forgot about that disappointing start and came all the way back to win 1-6, 6-1, 6-3 on Wednesday.

What was her mindset? “Just be aware and try not to get so negative on yourself. I think, for me, the score in the first set was very dramatic, but there was key points that I could have maybe won a game here or there,” Osaka said. “So I kept trying to tell myself that.”

This was, in some ways, a significant moment for Osaka, who once reigned atop women’s tennis, winning four Grand Slam titles — two at the Australian Open, two at the U.S. Open — and ascending to No. 1 in the WTA rankings. The victory allowed her to reach the third round at a major tournament for the first time since the 2022 season.

Getting to that stage was not considered a big deal at one point for her. But time off because of mental health breaks and then a pregnancy — Osaka’s daughter, Shai, was born in July 2023 — changed things.

Since returning to action a year ago, Osaka has shown signs of getting her game back together, including a memorable and narrow loss to then-No. 1 Iga Swiatek at the French Open.

Next for Osaka is a matchup against Tokyo Olympics gold medalist Belinda Bencic.

Muchova wasn’t the highest-seeded player to exit Wednesday. That was No. 5 Zheng Qinwen, the runner-up to Aryna Sabalenka at the 2024 Australian Open and the gold medalist at the Paris Games last August. Zheng lost a bit of focus after being called for a time violation and never managed to counter 97th-ranked Laura Siegemund’s strokes, bowing out 7-6 (3), 6-3 at John Cain Arena.

The player who beat Zheng in the final 12 months ago, No. 1-ranked Aryna Sabalenka, stretched her Melbourne Park winning streak to 16 matches as she eyes a third consecutive title, beating No. 54 Jessica Bouzas Maneiro 6-3, 7-5 at Rod Laver Arena.

Other women’s winners included No. 3 Coco Gauff, No. 7 Jessica Pegula, No. 14 Mirra Andreeva and No. 30 Leylah Fernandez.

Novak Djokovic added to his record collection by playing in his 430th career Grand Slam match and, though he dropped a set for the second outing in a row with new coach Andy Murray by his side, moved into the third round with a 6-1, 6-7 (4), 6-3, 6-2 win over Jaime Faria.

Other men advancing included No. 3 Carlos Alcaraz, who beat Yoshihito Nishioka 6-0, 6-1, 6-4. Seeded losers included No. 6 Casper Ruud, No. 22 Sebastian Korda and No. 27 Jordan Thompson.