Naomi Osaka fell at the first hurdle in her Grand Slam comeback on Monday, losing 6-4, 7-6 (7/2) to Caroline Garcia in the first round of the Australian Open.
Order of Play | Watch Live on DStv
A single break proved enough for the French 16th seed to win the opening set against her rusty opponent and she dominated the second set tie-break to progress in Melbourne.
Japanese star Osaka, who has won four Grand Slams, stepped away from tennis in September 2022, citing mental health concerns.
After giving birth to a baby girl, Shai, in July, she decided to return for the 2024 season.
Garcia paid respect to her defeated opponent after victory under the lights on Rod Laver Arena.
"I have a lot of respect for Naomi as a person and as a player," she said.
"She's been through a lot, but I'm just very glad to see her back and I hope she can enjoy the tennis now and have fun out there. She's a great girl.
"I mean, six months after giving birth she is playing quite amazing already, so we have to watch out."
Osaka's only competitive tennis before the Australian Open came at this month's Brisbane International, where she lost in the second round to Karolina Pliskova.
The two-time Australian Open champion went toe-to-toe with her French opponent at the start of the match.
But she double-faulted in the fifth game to hand Garcia a break point and then dumped a forehand into the net to surrender her serve.
The 26-year-old, who has tumbled to 831st in the world rankings, dug deep in her next service game to stay fighting in the set.
But the single break ultimately proved enough for Garcia.
Both players were solid on serve in the second set, with neither able to force the crucial breakthrough so it went to a tie-break.
Osaka faltered on her serve to slip to 3-2 and Garcia won all of the remaining points to seal the match, leaping for joy.
"I play tennis for this type of match," she said. "It was my first time at a Slam playing the second match in the evening after so many years on tour so I was excited by it.
"It will be a memory I will remember for many years. So win or lose, I wanted to have fun and experience it to the maximum."