Spanish superstar Alcaraz came through 7-6 (7/4), 6-3, 6-2 on Rod Laver Arena against hard-hitting German Yannick Hanfmann to take another step towards a career Grand Slam.

But the 22-year-old was put through his paces by a player 12 years older before setting up a showdown with France's Corentin Moutet.

"To be honest, it was tougher than I thought at the beginning," said Alcaraz, who already has six major titles but has never gone past the last eight in Melbourne.

"I didn't feel the ball that good. You know, the ball was coming as a bomb, forehand and backhand."

If Alcaraz does win the Australian Open to complete the career Grand Slam of all four majors, he would be the youngest man to do so, surpassing compatriot Rafael Nadal, who was 24 when he achieved that feat.

The unpredictable Medvedev, runner-up in 2021, 2022 and 2024, is trying to keep his emotions in check this year and was on his best behaviour against Frenchman Quentin Halys.

He lost a tight first set but the result was never in doubt as he surged to the finish line 6-7 (9/11), 6-3, 6-4, 6-2.

"It was a very tough match, happy I managed to fight," said the Russian, who faces Fabian Marozsan of Hungary next.

American Tommy Paul, Argentine duo Francisco Cerundolo and Tomas Etcheverry, Spaniard Alejandro Davidovich Fokina and Russian Andrey Rublev also safely negotiated the second round.

Heavy rain fell late in the evening, delaying Zverev's match against France's Alexandre Muller for more than 30 minutes.

The break failed to derail the German's victory charge, which resumed under a closed roof, as he won 6-3, 4-6, 6-3, 6-4.

Zverev, who faces Britain's Cameron Norrie in the third round, needed physio treatment for what appeared to be a lower leg injury.

"I took a painkiller and it was fine after that," said Zverev, who is still searching for a maiden major aged 28.

Great home hope Alex de Minaur, the sixth seed, dropped the first set to Hamad Medjedovic of Serbia but fought back to go through in four sets.

- 'Near perfect' -

World number one Sabalenka started in imperious mood.

The four-time major winner raced into a 5-0 lead over qualifier Bai Zhuoxuan, ranked a lowly 702, on centre court before wobbling to give the Chinese player a glimmer of hope.

But the top seed quickly snuffed it out to race home 6-3, 6-1 and set up a clash next with Russian-born Anastasia Potapova, now representing Austria, who dispatched 2021 US Open champion Emma Raducanu.

"Super-happy to close the (first) set, it gives me confidence that my game is there, my focus is there," said Sabalenka, who is bidding for a third Australian Open title in four years.

"Step by step. Super-happy with my win. There is always a little gap to improve."

Sabalenka has dropped just nine games so far as she looks to make amends for her upset in last year's final to Madison Keys.

Third seed Gauff was clinical against Serbia's Olga Danilovic, who ended Venus Williams's tournament in round one.

The two-time major winner took just 78 minutes to race home 6-2, 6-2 on Margaret Court Arena.

It set up a showdown next against fellow American Hailey Baptiste, ranked 70, who downed home hope Storm Hunter in straight sets.

"Near perfect," said Gauff, whose best performance in Melbourne was a semi-final in 2024.

Ukrainian 12th seed Elina Svitolina, Turkish prospect Zeynep Sonmez and in-form Canadian teenager Victoria Mboko also won on day four, all sweeping past their opponents in straight sets.

Mirra Andreeva, the 18-year-old Russian sensation, underlined her talent with an impressive 6-0, 6-4 victory over Maria Sakkari of Greece.