Stefanos Tsitsipas backed up his victory over Roger Federer by reaching the last four of the Australian Open but now finds Rafael Nadal standing in his way of a first grand slam final.

Following up breakthrough moments is notoriously difficult but 20-year-old Tsitsipas bucked the trend by battling to a 7-5 4-6 6-4 7-6 (2) quarter-final win over Spain's Roberto Bautista Agut on Rod Laver Arena.

It was another blow for the next generation but, while Novak Djokovic and Nadal continue to hoover up slam titles, all talk of a changing of the guard remains on hold.

Nadal has looked very much the form man in Melbourne, despite having not played a match since September prior to the first round, and swept past another up-and-comer in American Frances Tiafoe 6-3 6-4 6-2 to reach a 30th slam semi-final.

Tsitsipas described his run as like a fairytale but this is very much a story he has been writing for himself and he revealed he told his team in the off season that one of his targets for the year was to reach a slam semi-final.

It is apt that Tsitsipas once again meets Nadal at a breakthrough moment having lost to him twice last year in his first two ATP Tour finals in Barcelona and Toronto.

The Greek said: "I felt very close to beating him in Toronto. I remember coming back to the locker room and promising to myself I'm going to do much better against him next time.

"It felt like I understood a bit better what he was doing on the court after that match, and especially on hard court. On clay, it was a different story. I felt like I had no chance.

"It's going to be interesting. I feel all right with my game. I feel like I can do something good against him."

Nadal admitted he only watched the first set of Tsitsipas' victory over Federer before going out to dinner with his team, but he is well aware of the talents of the 20-year-old.

"When Federer is on court, it's always a surprise when he loses," said the second seed. "But we know they are good. We know that Stefanos is one of these players that can win against everybody. It was a surprise but not a very big surprise. I know Stefanos is ready to win against everybody."

Tsitsipas' achievement makes him the youngest man to reach the last four at Melbourne Park since Andy Roddick in 2003 and the youngest at any slam since Djokovic at the US Open in 2007.

Tiafoe, meanwhile, sees no reason why Tsitsipas cannot continue his run and believes his generation are ready to seize the mantle.

The charismatic 21-year-old said: "Why not? I think the game's definitely heading that way. Rafa and these cats ain't getting any younger, you know what I'm saying?

"We're playing good. Put us in the right situation at the right time, we'll take it. Granted, I didn't tonight, but it's coming."

It has been a remarkable run for Tiafoe but, after nearly running out of steam against Grigor Dimitrov two days ago, he was always unlikely to be able to stay with Nadal.

"It was tough definitely," he said. "He's a hell of a player. His ball is kicking up like crazy. The court was really slow.

"I knew if he got hold of a forehand, it was going to be barbecued chicken. My body was definitely hurting. I'm more or less happy to be done."

But Tiafoe will leave Melbourne firmly believing he belongs on this stage.

"It's crazy," he added. "I didn't think any of this was going to happen. If you would have told me during the off-season, 'You're going to play Rafa in the quarter-finals on Rod Laver with Rod Laver watching', I probably would have laughed.

"To be in a quarter-final at a slam, knowing I can do this, that's the biggest thing."