Doubles from record-breaker Lisa De Vanna and Caitlin Foord helped Australia overturn an early deficit in Carson, with Katrina Gorry also adding her name to the scoresheet on Friday (AEST).
Sam Kerr was irrepressible, winning a first-half penalty to earn an equaliser before providing two assists and icing the match with Australia's sixth goal.
The comprehensive win was the Matildas' third in a week and delivered their first piece of silverware since the 2010 Asian Cup.
While this tournament is only a friendly series, a first-ever win over world champions USA and victories over highly-ranked Japan and Brazil make it arguably the Matildas' greatest success.
The triumph over Brazil came despite an early setback.
Skipper Elise Kellond-Knight conceded a free kick in the opening minute, which Tamires rolled across the box for Camila to score from.
The replay made for excruciating viewing, as the ball trickled home within the reach of three defenders and goalkeeper Mackenzie Arnold.
Five minutes later, Kerr helped Alen Stajcic's team get back on level terms.
The in-form striker was hauled down in the box by Bia Zaneratto, allowing De Vanna to equalise from close range after her initial spot kick was saved.
Arnold's fine save and quick release allowed Australia to take the lead, with Foord finishing an end-to-end move just after the half hour.
Having provided Foord's assist from the right, minutes later Kerr played in De Vanna from the left and the veteran made no mistake to make the score 3-1.
De Vanna's brace moved her ahead of Kate Gill as the Matildas' all-time leading goalscorer, with 42.
Australia maintained the rage, with star midfielder Gorry beating two defenders and striking a sweet individual goal.
After the break, Foord made it five by latching onto substitute Tameka Butt's fine through ball and rounding the keeper.
With 10 minutes remaining, Kerr then bustled her way through a bruised Brazilian defence, poking home past Dani Neuhaus.
The only negative for Australia was an ankle injury to Chloe Logarzo, who was taken off in agony in the first half.