MELBOURNE, Australia — Two-time Australian Open champion Naomi Osaka stopped playing because of an injury after dropping the opening set of her third-round match against Belinda Bencic on Friday.

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, then was off the tour while pregnant. Her daughter, Shai, was born in July 2023.

Osaka began this season 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 an abdominal injury.

“At this moment, I just feel for Naomi,” Bencic said in her on-court interview. “I saw her struggling a little bit in the end of the set. Obviously, it’s not the way you would like that match to end.”

On Friday, Osaka — a former No. 1-ranked player who owns 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 US Open runner-up Leylah Fernandez, who faced each other 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 in 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.

The Associated Press contributed to this report.