Roger Federer has lifted the lid on the locker-room advice he offered Alexander Zverev following the German's shock defeat to Hyeon Chung at the Australian Open.

The 20-year-old fourth seed was beaten in five sets by the world number 58, leaving Zverev "crushed" according to the 19-time grand slam champion.

In his despair, Zverev found comfort in the words of Federer, who was keen to impart some of his own wisdom on one of the brightest young talents in the sport.

"After a match like today... he's still very young, still up-and-coming to some extent. He's still seeking the breakthrough on the grand slam level," Federer said of Zverev, who has never been beyond the fourth round of a major.

"I just think it's important to sometimes take a step back and actually see the good things you've done, give yourself time, maybe set the bar a bit lower.

"First let's maybe try to look for a quarters or a semi-finals, not just right away think, coming to the Australian Open or the US Open, I have to win this thing.

"I know people talk, but for the player, it's not easy if you've never been there. I remember I had a hurdle to pass the quarters. I only did that back in 2003 for the first time. I was 22. Either I played quarters or I lost first round.

"That's what I told Sascha [Zverev]. I said: 'Be patient about it. Don't put yourself under unnecessary pressure. Learn from these mistakes.

"'Whatever happened happened. Unfortunately, you have to believe in the process you're right now in. You had a good off-season. You're working hard. You're doing the right things. It's maybe not paying off at the slam level, but just stay calm, don't dig yourself in a hole.'

"There's no reason for that right now, I think. There's already enough stuff and pressure from you guys [the media].

"I just thought some nice words would maybe cheer him up, get him over the loss a few more hours earlier than it normally would.

"It's supposed to hurt. I'm sure it did. He looked crushed when I saw him.

"I gave him a tap on the shoulder and said: 'Come on, it's not too bad. It could be worse.'"

Federer booked his own place in the fourth round with a straight-sets win against Richard Gasquet, setting up a clash with Marton Fucsovics.