Ashleigh Barty led the way and debutante Priscilla Hon was her reliable sidekick as Australia knocked the US out of the Fed Cup to set up a home world group semi-final with Belarus.
The US had the home crowd at Asheville, North Carolina's US Cellular Center indoor arena on Sunday but Australia possessed world No 13 Barty who was invincible.
She demolished US number two Sofia Kenin in the first singles rubber on Saturday, followed up with 6-4 6-1 victory on Sunday against top-ranked Madison Keys and headed into the doubles decider alongside 20-year-old Hon with the world group tie locked 2-2.
Barty and Hon comprehensively beat experienced American duo Nicole Melichar and Danielle Collins 6-4 7-5 to book the Belarus match-up.
"We've had a hell of a weekend and there's absolutely nothing better than coming out and playing a live tie for your country," Barty said.
"For Pri to play the way she played today, I'm just so proud of her."
Hon has a singles ranking of 143, is 125 in doubles and had never played competitively partnered with Barty, but she showed no nerves against the Americans.
"This is my dream come true," Hon said.
"I've always wanted to play for Australia and beside Ash.
"I've always looked up to her my whole life."
Hon was not originally selected for doubles but captain Alicia Molik shook things up for the crucial second day.
Kimberly Birrell, who was outclassed by Keys in Saturday's singles rubber, was benched by Molik for out-of-form Daria Gavrilova, ranked 47 in the world.
It was a risk, with Gavrilova winless in 2019.
She put up a fight but fell to Collins 6-1 3-6 6-2 to square the tie for the US and set up the doubles decider.
Gavrilova was pencilled in but Molik instead slotted Hon alongside Barty and they played like a veteran doubles team.
Australia will play Belarus in April at an Australian location to be decided, giving Barty, Molik and their team a huge advantage in reaching the Fed Cup final.
"We love playing at home," Molik said.
"I mean, we've travelled so much.
"As Australians, we probably spend more time on the road than players from other nations so the fact we have a tie at home, it's important to us."
It is the first time since 2014 Australia has made the semi-finals.
The other semi-final will be France against Romania.