Stefanos Tsitsipas believes he can go all the way at the Australian Open after stunning double defending champion Roger Federer in the fourth round.

The Greek, seeded 14th in Melbourne, fought back from behind to seal a sensational four-set victory over Federer on Sunday - the Swiss' first loss at the tournament since the 2016 semi-finals.

Tsitsipas, the first player from his country to reach the last eight of a grand slam, will take on Roberto Bautista Agut in the quarter-finals and the world number 15 knows now is not the time to sit back and reflect on his achievements.

"I try to take every match differently. For sure it's a good win against Roger," he told a news conference.

"We all know who Roger Federer is, what he has done in tennis. But I still have to keep my focus, keep my concentration on further goals that I want to achieve. That's a very good beginning."

"I need to stay humble. This win is a good milestone, let's say good first step, as I said, to something bigger. I do feel like my game is pretty good at the moment."

"I feel confident. That's very important. I'm really pumped and excited to be competing in the quarter-finals two days from now. I'm really waiting for that moment."

Asked if he could go all the way and lift the trophy, Tsitsipas replied:

"For sure. That's why I'm here. That's why I'm playing, for the trophy, for the title."

"Yeah, again, I feel good. I really want it badly. I really want to proceed further in the tournament, to make myself happy and the people that are cheering for me happy."

"I really like this atmosphere that's on the court, the whole dynamic of it, I would say. It just feels so nice to be playing on these courts. It's spectacular. I really want to stay here as long as possible. That's my goal."

And Tsitsipas revealed he had analysed some of Federer's previous matches on YouTube - including a US Open defeat against a player whom the Greek opted not to identify.

"I did watch a couple of his matches in the past that he played on hard courts. I kind of watch some highlights of players that beat him in grand slams. It was actually not Rafa [Nadal], [Novak] Djokovic, but some other players that have beaten him in the past US Open."

"Very similar game style like me. I will not say which player. He did beat him in US Open a few years ago. It was a good example to see the way he played, the way he fought into the match to get that win. I'm pretty sure that helped."