Alex Zverev became the first man through to the semi-finals of the Australian to strike a blow for the next generation.
The German is now just two matches after from winning his first Grand Slam – and donating his A$4.12m (£2.1m) first prize to Bushfire Relief.
Former Wimbledon champions Simona Halep and Garbine Muguruza will meet in the second women's semi-final on Thursday.
And Jamie Murray and his American partner Bethanie Mattek-Sands are through to the last four of the mixed doubles – while Martina Navratilova and John McEnroe have issued an apology.
Rafa Nadal, who was not allowed into the player's area because he did not have his pass, plays Dominic Thiem later. Roger Federer plays Novak Djokovic on Thursday.
First Grand Slam semi-final for world No.7 Zverev
The German, 22, beat former champion Stan Wawrinka, 1-6 6-3 6-4 6-2 to reach the last four for the first time – and guarantee he will donate A$50,000 to Bushfire Relief (A$10,000 for each win). But Zverev also pledged before the tournament that he would give the winner's cheque if he triumphs on Sunday.
Zverev said: “It is easy to say in the first round, right! Yes, it is still true. I hope I can make it happen.
“I made the people of Australia a promise. I will keep that promise if it happens. I am not money-driven - my parents taught me.
“Four million Australian dollars would be nice, I could buy a few cars. But there’s people that need it for rebuilding the lives they once knew. It is much more important that they get that money.”
Halep gets done double quick – then goes shopping
The 2018 finalist here needed only 53 minutes to beat Anett Kontaveit 6-1 6-1 – the Estonian coached by Andy Murray's father-in-law Nigel Sears.
But rather than watch the second quarter-final, the Romanian said: "I will chill, I will just do some shopping like every day because it motivates me.
"Tomorrow I will think about the match, today nothing about tennis."
Muguruza reaches her first Australian Open semi-final
The Spaniard is back in the last four at a Grand Slam for the first time since the 2018 French Open by beating Russian Anastasia Pavlyuchenkova 7-5 6-3.
The former world No.1 is playing her first Grand Slam since 2014 not being seeded after struggling with her form and health.
She said: “It is always special to get deep in a Grand Slam. Very excited to be playing tomorrow again. It's a very long tournament.
"You have very tough opponents, not being seeded as well. I'm just happy that I'm going through every match.”
Jamie Murray is through to another Grand Slam semi-final
The seven-time Major champion and his American partner Mattek-Sands – who have won the last two US Opens together- beat Saisai Zheng and Joran Vliegen 6-3 6-4 to reach the last four for the first time together here.
The Scot said: “t’s exciting to be playing in the latter stages of a grand slam. Obviously doubles didn’t work out this year and I’ve got a great partner in Beth.
"We know that we’re one of the best teams in it. But mixed is always difficult, it’s very random sometimes how it can work out and, obviously, we’re playing match tiebreaks here so there’s not that much room to mess around or whatever.
"But we played three good matches so far, beat some good teams and excited to be in the semis”
Sorry not the hardest word for Martina Navratilova and John McEnroe
The two legends were blasted by furious Australian Open organisers for staging an onside protest against Margaret Court and displaying a home-made sign saying: “Evonne Goolagong Arena.”
Tennis Australia issued an angry statement criticising their “breach of protocol”
Today Navratilova said: “I had no idea there was this kind of protocol.
“Had I known, I would have done it differently. I said my piece. You can see my whole statement. I stand by that. But I apologise about breaking protocol. I did not need to do that.”
McEnroe, who was back doing post-match interviews in the Rod Laver Arena, said: “Admittedly I was never one to study the rule book carefully or for that matter, even at times abide by the rules.
“In this case, I was not aware of the Tennis Australia rules and protocol for issuing credentials. For that I apologize to Tennis Australia and recognize and appreciate the great job they have done to make the Australian Open a great event for the fans, players and myself”.