Rafael Nadal reached his first Grand Slam semi-final since 2014 with a superb 6-4 7-6 (9-7) 6-4 victory over Canada’s third seed Milos Raonic.
The 14-time Grand Slam winner, who has been troubled by injuries in recent years, saved six set points in the second set before dominating the third.
Nadal, the 2009 champion, faces 15th seed Grigor Dimitrov tomorrow after the Bulgarian beat David Goffin.
The Spaniard, 30, remains on course to meet Roger Federer in Sunday’s final.
Federer, 35, will play his fellow Swiss Stan Wawrinka in the first semi-final today.
Nadal is attempting to become the first man in the Open era – and only the third man in history after Roy Emerson and Rod Laver – to win each of the four Grand Slam titles twice.
The ninth seed’s victory means six of the eight players in the men’s and women’s semi-finals are over 30.
Nadal lost here in the first round to Fernando Verdasco 12 months ago and admitted to wondering if he may never again challenge for major honours.
“I think I am not a very arrogant person so I always have doubts,” he said.
“Even when I was winning I had doubts and even more so when I had injuries. But doubts make you work harder.
“I have had a great career but I had some tough moments so that makes me enjoy moments like this even more.”
Nadal last reached a Grand Slam semi-final when he won the French Open – his last major title – three years ago.
A wrist injury in 2016 raised serious concerns about his future but he looked close to his very best against Raonic.
He broke the big-serving Canadian once in the first set to take the lead but Raonic, who was the highest seed left in the men’s draw, looked like he would level the match in the second.
Raonic needed a medical timeout midway through the set for an abductor problem, but seemed to come back stronger and had three set points on Nadal’s serve at 5-4.
Nadal saved them all, then saved two more in the tie-break before Raonic double-faulted on the sixth set point, and the former world number one took the set with his first chance.
Nadal took advantage of Raonic’s lack of mobility in the third set to wrap up an impressive victory, his 50th since making his debut in the tournament in 2004, with a hold to love.
His win came after two hours and 44 minutes on court and he celebrated with a huge leap before falling to his knees as emotion took over.
Nadal was reluctant to talk about a possible dream final against Federer.
“Let me enjoy today, the victory, and being in the semi-final,” he said. “For me, it is great news. It is a good start of the season and now I have a very tough match against Dimitrov.”
Federer, who won the last of 17 Grand Slam titles at Wimbledon in 2012, has only just recovered from a knee injury that kept him out for six months.
“It is great for tennis that Roger is there again after an injury, after a lot of people talk about that probably he will never be back,” Nadal added.
“The real thing is that he’s back and he’s probably ready to win again, fighting again to win a major. And that’s good for the fans because Roger is a legend of our sport.”
Dimitrov, who works with Dani Vallverdu, former coach of Andy Murray and Tomas Berdych, had earlier beaten 11th seed Goffin 6-3 6-2 6-4.
The 25-year-old began the year with a title in Brisbane and has now won 10 matches in a row.
“The last two years have been a rollercoaster for me, but I’m happy with the way it happened,” said Dimitrov.
“I’m appreciating things much better now. To be back in the semi-finals of a Slam means too much for me right now.”
He will be appearing in his second major semi-final, having made it to the same stage at Wimbledon in 2014.