Australian Open champion Naomi Osaka's Grand Slam comeback ended abruptly Monday, crashing out to Caroline Garcia, but US Open winner Coco Gauff and men's third seed Daniil Medvedev surged on in Melbourne.
On a baking-hot day at Melbourne Park, men's seventh seed Stefanos Tsitsipas and women's sixth seed Ons Jabeur also tasted first-round victory.
But Wimbledon champion Marketa Vondrousova and veteran Andy Murray made early exits.
Japanese star Osaka, 26, stepped away from the sport in September 2022, citing mental health concerns.
After giving birth to a baby girl in July, she decided to return for the new season and was back at the scene of her title-winning exploits in 2019 and 2021.
But she was unable to rediscover her championship-winning form against 16th-seeded Frenchwoman Garcia after just two competitive games in Brisbane since returning.
«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,» said Garcia.
«I mean, six months after giving birth she is playing quite amazing already, so we have to watch out.»
Medvedev battled tough conditions on Margaret Court Arena against French qualifier Terence Atmane, who smashed his racquet, served underarm and retired in tears after suffering bad cramping that forced him off court while losing 5-7, 6-2, 6-4, 1-0.
«When I started to feel tough physically he started cramping, so it was brutal conditions,» said Russia's Medvedev, a finalist in 2021 and 2022.
«I was getting tired but many times in these situations the other guy is getting tired too and it's about who manages it better.»
The Russian will face Finland's unseeded Emil Ruusuvuori in the next round.
Tsitsipas,