World number two Daniil Medvedev steps up his march towards the Australian Open men's title later but the early action on Saturday was dominated by the resurgent former finalist Simona Halep, who swept into the second week in Melbourne.

Halep swatted aside Danka Kovinic, the conqueror of US Open champion Emma Raducanu, 6-2, 6-1 in just 64 minutes and will face French veteran Alize Cornet on Monday for a place in the quarter-final.

American world number 30 Danielle Collins, who seems to raise her game in Melbourne where she was a semi-finalist three years ago, is also through to the last 16 after battling past tenacious Danish teenager Carla Tauson 4-6, 6-4, 7-5.

The fit-again Halep came into the tournament full of confidence after her first title in 16 months earlier this month at a Melbourne warm-up event and was always in charge.

"I feel great that I can play the fourth round again. I always love to play in Australia so that's why maybe I play good matches," said Halep.

Seeded 14, Halep has been in insatiable form, dropping just nine games in her opening two matches, and she carried it into her clash against the 27-year-old.

Romania's Simona Halep was in insatiable form again as she swept into the last 16 on Saturday Romania's Simona Halep was in insatiable form again as she swept into the last 16 on Saturday Photo: AFP / Martin KEEP

Cornet slugged it out with Slovenia's 29th seed Tamara Zidansek for a 4-6, 6-4, 6-2 victory and said she was just glad to get through on a hot day.

"It was mostly about survival," said Cornet, who produced a stunning upset of world number three Garbine Muguruza in round two.

"The Australian heat is brutal and I can't believe I won."

Second seed Aryna Sabalenka, who has been plagued by poor serving in Australia, was later playing 31st seed Marketa Vondrousova of the Czech Republic.

The Belarusian dished up 19 double faults in scraping through her second-round match against China's Wang Xiyu in three sets on Thursday and can't afford a repeat.

Russia's Daniil Medvedev celebrates after beating Australia's Nick Kyrgios in the second round Russia's Daniil Medvedev celebrates after beating Australia's Nick Kyrgios in the second round Photo: AFP / William WEST

In the men's draw, US Open champion Medvedev cemented his status as tournament favourite by overcoming the mercurial Nick Kyrgios in four sets in a raucous second-round encounter.

Medvedev, the de facto top seed after Novak Djokovic was deported on the eve of the tournament, faces a more conventional opponent in Dutch world number 57 Botic van de Zandschulp for a place in the last 16.

But he will not take his opponent lightly. "Grand Slams are tough, there are going to be tough opponents," said Medvedev.

"Sometimes you lose early, sometimes you lose late, sometimes you win it. I just want to play really good."

With Andy Murray and Raducanu out, the weight of British expectation now falls entirely on the shoulders of 24th seed Dan Evans.

The last Brit standing had an unexpected day off on Thursday when his French opponent Arthur Rinderknech pulled out with injury giving him a walkover into the third round.

Evans faces in-form ninth seed Felix Auger-Aliassime, who was part of Canada's ATP Cup-winning team in Sydney earlier this month.

There is an intriguing clash between fifth seed Andrey Rublev of Russia and 2018 Melbourne Park finalist Marin Cilic of Croatia that has the potential to be a late-night classic on Margaret Court Arena.

Cilic pushed Roger Federer to five sets in the final four years ago and the big-serving 27th seed is capable of upsetting anyone.

Fourth seed Stefanos Tsitsipas is a potential semi-final opponent for Medvedev, but first he needs to get past seasoned Frenchman Benoit Paire on Rod Laver Arena.

Paire, the world number 56, is looking to equal his best at a Slam by reaching the fourth round at the Australian Open for the first time.