Australia's Alex de Minaur overpowered Emil Ruusuvuori 6-4 6-3 after Alexei Popyrin beat Otto Virtanen 7-6(5) 6-2 to earn the 28-times Davis Cup champions a 2-0 win over Finland on Friday that sent them into a second successive final.
Lleyton Hewitt's team, who lost to Canada in the 2022 final and missed the opportunity to close in on 32-times champions the United States, will face Serbia or Italy who meet in the second semi-final on Saturday.
Giant-killers Finland were the only country left in Malaga to have not won a Davis Cup crown after the Netherlands lost to Italy but their quest to make a first final in the elite men's team competition ended with a whimper.
De Minaur, who sparked Australia's comeback victory in their quarter-final against the Czech Republic, left the Finns with an uphill task as he showed his resolve to recover from an early break against Ruusuvuori and take the first set.
Ruusuvuori showed little sign of the shoulder problem that kept him out of Finland's stunning win over champions Canada in the last eight and played aggressively in the second set but De Minaur held firm.
World number 171 Virtanen earlier served with venom and let rip a blistering array of groundstrokes in a tight first set but came unstuck towards the end, as Popyrin saved a set point and pounced in the tiebreak.
Popyrin, a late replacement for the injured Thanasi Kokkinakis, grabbed the first break in the second set when Virtanen hit two successive double faults as Australia sensed an opportunity.
The 40th-ranked Popyrin closed out the win and silenced a huge crowd of boisterous Finnish supporters who have made the nearby town of Fuengirola their home.
"I think the majority of the fans were Finnish, apart from our little corner that we had behind the bench," Popyrin said.
"It's nerves that I've never experienced before in my life, the nerves playing the first tie, the first rubber of a Davis Cup, winning my first live rubber of a Davis Cup.
"I just had to keep my head steady and really focus on my serve and try to capitalise on opportunities when they came."
