The 20-year-old from Greece entered the tournament as the No. 14 seed. He defeated two unseeded opponents before knocking off No. 19 Nikoloz Basilashvii, No. 3 Roger Federer and No. 22 Roberto Bautista Agut.
But Nadal -- the No. 2 seed -- had little trouble dispatching of his young counterpart at Rod Laver Arena in Melbourne. The 17-time Grand Slam champion trailed 1-0 at the start of the first and second sets, but stormed back each time to take control of the match. He cruised to a 6-0 third set after winning 6-2, 6-4 in the first two sets.
"He has everything to become a multi-Grand Slam champion," Nadal told reporters. "When he's in the semifinals at that age, it says a lot of good things about him. I hope to face him in important rounds in the next couple of years hopefully."
Nadal, 32, now awaits the winner of the other semifinal between No. 1 Novak Djokovic and No. 28 Lucas Pouille for a shot at his second Australian Open title and first since 2009.
No. 4 Naomi Osaka defeated No. 7 Karolina Pliskova 6-2, 4-6, 6-4 her semifinal matchup to reach the women's Australian Open final. Osaka will face No. 8 Petra Kvitova, who defeated American Danielle Rose Collins in straight sets (7-6, 6-0).
"I don't necessarily think I played the best I've ever played," Osaka said. "For me, what I take away is that I never gave up. That's something that I'm really proud of myself for."
The women's final is at 3:30 a.m. on Saturday while the men's final is at 3:30 a.m. on Friday in Melbourne.