Stefanos Tsitsipas produced a stunning comeback to halt Rafa Nadal's march towards a record-breaking 21st career Grand Slam.
The Greek 5th seed came from two-sets to love down to beat Nadal in five.
Tsitsipas won the match 3-6, 2-6, 7-6, 6-4, 7-5 to set up a semi-final date with the Russian, Daniil Medvedev.
It's just the third time Nadal has taken a two-set lead and gone on to lose the match. In fact, Nadal hadn't dropped a set in this year's tournament until Tsitsipas won the third on a tie-break.
I’m speechless,” the Greek said on court afterwards, “I have no words to describe what just happened.
"It’s an unbelievable feeling to be able to fight at such a level and just be able to give it my all on the court.
“I started very nervous, I won’t lie, but I don’t know what happened after the third set. I just flied like a little bird, everything was working for me. The emotions at the end are indescribable."
"I fly like a little bird!" 🐦
A "speechless" Stefanos Tsitsipas attempts to explain the feelings of beating Rafa Nadal and reaching the #AusOpen semi-finals
— Eurosport (@eurosport) February 17, 2021
The 22-year old extolled the virtues of keeping a level-head in dispatching the 34-year old.
"Staying calm on court and holding my nerves is a very important element and having failed to do so in some of my matches, I think I would also give a big part of my win to that," he said.
“Be consistent with my mood and just stay calm in the crucial tight moments, that helped a lot.
“My mood was consistent. I was working a lot on trying to just keep everything to myself and it’s also something I’m really happy with, the attitude I showed on court.”
Fourth seed Medvedev awaits in the semis, after he felled fellow Russian Andrey Rublev in straight sets.
With the win, he became just the fifth Russian to reach the semi-finals in Melbourne. He follows hot on the heels of qualifier Aslan Karatsev in joining the ranks of Marat Safin, Yevgeny Kafelnikov and Aleksandar Metreveli.