Rafael Nadal sailed into the second round of the Australian Open on day two before backing "humble" fellow Spaniard Carlos Alcaraz to have a "great career" following his maiden grand slam win.

Nadal cruised to a 6-3 6-4 6-1 victory over Laslo Djere on Rod Laver Arena on Tuesday and will face Michael Mmoh in round two.

The Spanish great's compatriot Alcaraz won his first major match at Melbourne Park, seeing off fellow qualifier Botic Van de Zandschulp 6-1 6-4 6-4.

Murcia native Alcaraz has been billed by Nadal's uncle and former coach, Toni Nadal, as his nephew's "natural replacement" and the 20-time grand slam champion says the 17-year-old has all the ingredients to have a great career.

The second seed said: "He's very good. He's very young. He has everything to improve in the future with his age.

"He already is where he is, and he has a lot of great things on his game. I really believe that he will have a great future because he's a good guy, humble, hard worker. He has a lot of positive things."

Daniil Medvedev outclassed Vasek Pospisil 6-2 6-2 6-4, while Stefanos Tsitsipas eased past Gilles Simon 6-1 6-2 6-1, but fellow seed David Goffin lost a five-set marathon with Alexei Popyrin.

Nadal happy to 'survive' 

Nadal missed the ATP Cup before starting his quest for a record 21st grand slam title at Melbourne Park due to muscle tightness in his back.

He was simply happy to clear the first hurdle on the second day of the tournament.

"I needed to survive today and that's what I did. I just tried to be focused all the time, tried to get through," he said.

"For me personally, [I'm] happy to be through to the second round. I did I think a good job today. Straight sets, that's what I did."

Tennys disgruntled over 'joke' of preparation

American Tennys Sandgren was among over 70 players who were locked down in a hotel for a fortnight before the tournament due to positive COVID-19 test on their flight to Australia.

Sandgren made no secret of his displeasure over the restrictions he was forced to adhere to and let his feelings be known again after the two-time quarter-finalist lost 7-5 6-1 6-1 to Alex de Minaur on John Cain Arena.

He said: "How would you imagine prepping for a hot kind of muggy day, three-out-of-five sets against a player like that, that calibre, when you can't play tennis? You can't go outside? You can't. It's impossible. It's impossible.

"So I played last week's event [the Great Ocean Road Open], which probably wasn't a good idea. It wasn't hot, it was very mild conditions, and I played two hard three-set matches and I've never been more sore in my life after the second round, and I took two days off because I couldn't walk, and then I hit a couple times before today. I mean, it's just kind of a joke of preparation. But yeah. What are you going to do?"

Alcaraz escaping social media hype

Big things are expected of teenager Alcaraz and there was more hype over his potential after an impressive first-round win.

Alcaraz just wants to do his own thing and show why the likes of Rafael and Toni Nadal speak so highly of him.

"So I try to be focus on me, not on the social media, to play my game, play in front of my team, to my team, to me, my family," he said.

"I try to, yeah, to be a part of the social media and don't hear the comparison with Rafa. Yeah, I try to do this."

Daniil Medvedev and Andrey Rublev produced ruthless performances as Russia cruised into the ATP Cup semi-finals.

Russia followed up their day-one win over Argentina with victory against Japan to ensure they will finish top of Group D.

Rublev got things rolling with an emphatic 6-1 6-3 win over Yoshihito Nishioka and Medvedev dispatched Kei Nishikori in a 6-2 6-4 triumph.

Those results meant the subsequent doubles match – which Japan won – would not be relevant.

"I am really happy for the team," said ATP Finals champion Medvedev, who has now won 12 matches in a row on the tour.

"Reaching the semi-finals is a big step – I am really happy that we made it in both singles. Both matches were straight sets, so really happy for the team and hopefully we can go further than that."

Italy, who had beaten Austria on the opening day, are also through after Fabio Fognini and Matteo Berrettini earned wins in straight sets over France duo Benoit Paire and Gael Monfils on Wednesday.

France play Austria next but neither team can catch Italy in Group C.

Alexander Zverev won a thriller against Denis Shapovalov 6-7 (5-7) 6-3 7-6 (7-4) to ensure Germany defeated Canada.

It was a first win at the ATP Cup for US Open runner up Zverev, who had a miserable tournament in 2020.

That sets up a day three contest for Germany against Novak Djokovic and Serbia where the winning team will progress to face Russia.

KYRGIOS AND WAWRINKA THROUGH

Nick Kyrgios – playing his first tournament for a year – made it two wins from two at the Murray River Open, defeating fellow Australian Harry Bourchier 6-2 7-6 (9-7).

First seed Stan Wawrinka survived a scare before prevailing against Mikhail Kukushkin to win 4-6 6-3 6-1 in just under two hours.

Wawrinka will take on Alex Bolt in the last 16, while Kyrgios should be tested against fourth seed Borna Coric.

At the Great Ocean Road Open, top seed David Goffin crashed out as world number 146 Carlos Alcaraz celebrated a shock 6-3 6-3 victory.

Karen Khachanov and Jannik Sinner were among the seeds who progressed, both winning without dropping a set.