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.
“I felt very close to beating him in Toronto,” said Tsitsipas. “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.”
Tsitsipas’s 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.
For Tiafoe, it has proved a remarkable run in Melbourne but, after nearly running out of steam against Grigor Dimitrov two days ago, he was always unlikely to keep up 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.”
In the women’s draw, an emotional Petra Kvitova cried “happy tears” after reaching the semi-finals of a grand slam for the first time since the horrific stabbing that almost ended her career.
It is only two years since the Czech was watching the Australian Open on TV wondering whether she would ever play to the same level again after the tendons and nerves of the fingers in her playing hand were damaged in the attack by an intruder at her home.
After beating home hope Ashleigh Barty 6-1 6-4, Kvitova was asked by Jim Courier in an on-court interview whether she had thought she would be back on such a stage.
With tears in her eyes and her voice wavering, Kvitova said: “I didn’t really imagine to be back in this great stadium and play with the best. It’s great.”
“I thought that question will come,” she added in her press conference later. “It was kind of a mix of emotions of everything I’ve been through.
“Sometimes I’m not really recognising anything from the past. But, when Jim asked that, it wasn’t really easy for me to see myself being in a semi-final after everything.
“I always wanted to come back and play on the highest level I can, compete with the best, play the grand slams, actually be very deep in the grand slam, which is happening.
“I’m calling it my second career. So it’s the first semi-final of the second career.”
Kvitova has been in ruthless form, not losing more than five games in any of her matches so far to make the last four at a slam for the first time since winning her second Wimbledon title in 2014.
She and Barty, who was the first Australian woman to make it this far in Melbourne for a decade, had contested a very close final in Sydney a week and a half ago but this time Kvitova was simply too good.
Unseeded American Danielle Collins continued her remarkable run on her debut at the tournament by seeing off Anastasia Pavlyuchenkova 2-6 7-5 6-1.
The 25-year-old was ranked outside the top 100 a year ago and arrived in Melbourne having never won a match in the main draw of a slam.