Wednesday's semi-final victory saw Wiegman become the first coach to guide two different countries to a Women's World Cup final, after she took her native Netherlands to the 2019 showpiece match, where they were defeated by the United States.
It also left reigning European champions England, who face fellow first-time Women's World Cup finalists Spain in Sunday's title decider in Sydney, on course for a notable double.
"We achieved the final!" Wiegman told the BBC. "It's unbelievable, it feels like we won (the tournament) which we didn't, we just won this game - in an incredible stadium, an away game, the way we played - it was a hard game, but we found a way to win again."
'Ruthlessness'
The 53-year-old added: "People have been talking about ruthlessness all the time, in this team there is ruthlessness, up front or in defence."
As for her own achievement in again reaching a Women's World Cup final, Wiegman said: "Having the chance as a coach or a player to make it to two finals is really special. I never take anything for granted, but it's like I'm living in a fairytale or something."
England went ahead through Ella Toone's 36th-minute strike into the top right corner before Australia heroine Sam Kerr, making her first start of the tournament, equalised with a long-range shot in the 63rd minute.
Lauren Hemp, however, restored England's advantage in the 71st minute after firing into the bottom far corner from Millie Bright's long ball upfield.
Alessia Russo put the result beyond doubt four minutes before full-time, beating Australia goalkeeper Mackenzie Arnold with a low shot.
"When they (Australia) scored they got momentum, the place erupted and then Hempo's goal just flipped the momentum which was crucial so to get 3-1 you can settle a bit and see the game out," said Russo.
Lifelong dream
The 24-year-old forward, asked about England's prospects in the final, added: "Spain are going to be even tougher... But we've been dreaming since we were little girls. We're excited, we'll recover and be ready."
For 31-year-old England defender Lucy Bronze, twice a losing semi-finalist, Wednesday's win had additional significance.
"The one thing I've always wanted to do is get to a World Cup final," said Bronze, who plays her club football with Spanish side Barcelona.
England have now reached their first football World Cup final since the men's team beat West Germany 4-2 at Wembley back in 1966.
Wednesday's win sparked numerous tributes to the Lionesses, with England men's captain Harry Kane telling Sky Sports: "Massive congratulations to the Lionesses... We are all behind them and hopefully they can do it in the final."
There was royal approval too, with King Charles III -- the head of state in both Britain and Australia - saying in a statement: "My wife (Queen Camilla) and I join all our family in sending the mighty Lionesses our warmest congratulations on reaching the final of the World Cup, and in sharing our very best wishes for Sunday's match.
"While your victory may have cost the magnificent Matildas (Australia) their chance for the greatest prize in the game, both teams have been an inspiration on and off the pitch - and, for that, both nations are united in pride, admiration and respect."
His son Prince William, the heir to the throne and president of England's Football Association, tweeted: "What a phenomenal performance from the @Lionesses – on to the final!
"Commiserations to @TheMatildas you've played brilliantly and been fantastic co-hosts of this World Cup."
