Having raced into a two-set lead, the Spaniard faced a resurgent Tsitsipas who won three straight sets — the only three sets Nadal has dropped all tournament — to knock him out of the quarterfinals.
The five-set thriller — which finished 3-6 2-6 7-6 (7-4) 6-4 — took over four hours and finished close to midnight in Melbourne, but the relief and delight was evident on the Greek’s face in celebration.
His victory advances him to the tournament’s semifinals where he will face Daniil Medvedev.
“It’s an unbelievable feeling to fight at such a high level and leave it out on the court. I started very nervously. I don’t know what happened after the third set. I flew like a bird and everything worked for me.”
Despite entering the Australian Open with an injury cloud hanging over him and looking to create men’s history by winning his 21st grand slam, surpassing the record he shares with Roger Federer, Nadal had looked imperious from the get-go.
The 34-year-old hadn’t dropped a set on his way to the quarterfinals and that form continued from the start against fifth seed Tsitsipas.
Although the Greek looked to be aggressive from the outset, Nadal showed his experience and class, maneuvering the 22-year-old and dissecting the court at will.
Early breaks in the opening two sets and dominance with his serve allowed the 20-time grand slam winner to race into a two-set lead in just over an hour.
However, Tsitsipas eventually found his feet in the third set. He didn’t drop a service game and, after taking Nadal to a tie break, he managed to get a set back and inflict the first dropped set on Nadal at this year’s competition.
And in the fourth set, Tsitsipas looked far more impressive and competitive, forcing Nadal to defend multiple break points as his own service games passed with more ease.
The fifth and final set followed the same mold, with players holding serve until the 11th game of the set when, showing some remarkable resilience, Tsitsipas broke the veteran’s serve, leaving him serving for the set, match and a spot in the semifinals.
Despite the world No. 2 showing his champion’s spirit by testing his younger rival, Tsitsipas held serve to advance to his second Australian Open semifinals.
Earlier on Wednesday, Medvedev got the best of his compatriot and friend Andrey Rublev to book his place in the semifinals.
The fourth seed, who blitzed Rublev 7-5 6-3 6-2 on Rod Laver Arena, has now won 19 consecutive matches dating back to the start of last year’s Paris Masters.
“[Medvedev] plays very well and has been very consistent, with lots of consecutive wins,” said Tsitsipas.
“I need to recover and have a good ice bath. I am looking forward to the match and each match I play here is an opportunity to play my best tennis. It will be amazing to see the crowds again.”
The other semifinal will be contested between Novak Djokovic and Aslan Karatsev.