Two-time Australian Open champion Naomi Osaka stopped playing because of a strained abdominal muscle after dropping the opening set of her third-round match against Belinda Bencic on Friday.

“I kind of have a history of it, since I was a teenager. At least once a year, I’d get an ab strain. For me, I want to say it’s more the way my serve is — it’s quite explosive,” Osaka said, explaining that she got hurt at a tournament in Beijing, where she retired from a match against Coco Gauff on Oct. 1. “Unfortunately, it carried on over to the beginning of this season.”

This was Osaka’s first run to the third round at a major tournament since 2022. She missed time in recent seasons because of mental-health breaks, then was off the tour while pregnant.

Her daughter, Shai, was born in July 2023.

Osaka began 2025 by making it to the final of a tournament at Auckland, New Zealand, on Jan. 5, but she stopped playing in the title match there because of the abdominal injury.

Then, she said, the problem got “way worse” after her second-round win in Melbourne on Wednesday against 2023 French Open finalist Karolina Muchova.

“It was, I guess, a little inevitable, but I think the competitor in me just wanted to see it through to the end,” Osaka said. “I just hope that I can figure it out and figure out how to get healthy in time” before the tour heads to events at Indian Wells and Miami in March, she added.

On Friday, Osaka — a former No. 1-ranked player who owns a total of four Grand Slam titles — was visited by a trainer during the changeover while she led 6-5. The trainer examined Osaka’s abdominal area and gave her a pill to take, and play resumed.

Just before the tiebreaker began, Osaka went over to her courtside coaches’ box and chatted briefly with Patrick Mouratoglou.

After Bencic claimed that set in a tiebreaker by a 7-6 (3) score, taking four of the last five points via unforced errors by Osaka, the chair umpire announced that the match was over after 57 minutes, “due to injury.”

The two players hugged on the sideline, and Osaka left the court. She won the Australian Open in 2019 and 2021, and the US Open in 2018 and 2020.

“Hopefully she’ll be fine soon and be able to play the rest of the season,” said Bencic, who won a singles gold medal for Switzerland at the Tokyo Olympics in 2021.

Bencic, who is also a mother, drew a heart on the lens of a courtside TV camera and wrote: “Get well soon Mama.”

Next for Bencic will be a fourth-round matchup against 2023 US Open champion Coco Gauff or 2021 U.S. Open runner-up Leylah Fernandez, who were scheduled to face each other on Friday night.

“I’ll watch a bit, if I can,” Bencic said, “but I think I’ll do my cooldown and try to focus on my recovery.”

Bencic, who returned to action last October after having her first baby, has never been past the fourth round in 11 past appearances at Melbourne Park.

She lost at that stage a year ago to two-time champion Aryna Sabalenka.