MELBOURNE, Australia (AFP) — Two-time finalist Daniil Medvedev and US Open champion Coco Gauff swept into the second round of the Australian Open on Monday, but Wimbledon winner Marketa Vondrousova was sent packing.

On a baking-hot day at Melbourne Park, men's seventh seed Stefanos Tsitsipas and 16th seed Ben Shelton also tasted victory, ahead of Naomi Osaka's Grand Slam comeback on Rod Laver Arena in the evening session.

Third seed Medvedev battled tough conditions on Margaret Court Arena against French qualifier Terence Atmane, who smashed his racket, 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, who lost last year's final to Novak Djokovic, was stunned by Belgian lucky loser Zizou Bergs in the first set but woke up to take complete control and win 5-7, 6-1, 6-1, 6-3.

The Greek star was due to meet Italian Matteo Berrettini, but the former world No. 6 withdrew with a foot injury on Sunday.

Women's fourth seed Gauff said ahead of the opening Grand Slam of the year that she wanted to win "multiple" major titles after her breakthrough at Flushing Meadows in 2023.

The 19-year-old put the plan into motion with a 6-3, 6-0 rout of Slovakia's 68th-ranked Anna Karolina Schmiedlova on center court.

"I was a little bit nervous coming in today. Probably could tell. I was able to just calm down and then play my good, not my best, but good tennis," said Gauff, who successfully defended her Auckland title in the lead-up.

Her reward is a clash with unseeded American Caroline Dolehide in Round 2.