After a shock 3-2 defeat by Nigeria, the Matildas risked joining New Zealand on the discard pile, which would have been a crushing blow for tournament organisers as well as home fans.
Instead, Tony Gustavsson's Australia found their groove without the services of injured captain Sam Kerr to eliminate Canada and send most of the 28,000-strong Melbourne crowd home happy.
The win garnered rave reviews in the nation's newspapers on Tuesday.
"This gift of a home World Cup is meeting all its KPIs," sports writer Greg Baum said in The Age newspaper.
"But in the end, only one criterion counted and will count. It was, and is, down to the Matildas and particularly Sam Kerr."
Australia's opening match against Ireland drew 75,784 fans to Stadium Australia in Sydney, a record crowd for a women's soccer match in the country.
The Matildas' return to the venue next week for their round of 16 clash could test the mark. Their opponents will be decided after the games to be played on Tuesday.
"Every single fan out there, thank you!" a fired-up Gustavsson said after the Canada rout, jabbing his finger into a TV camera.
More than 1.6 million tickets have been sold across Australia and New Zealand for the tournament so far.
Crowds have been particularly healthy in Australia, even for non-Matildas matches.
Some 40,000 spectators flocked to the Sydney Football Stadium to see Colombia upset heavyweights Germany 2-1 on Saturday, with the South American nation's fans creating an electric atmosphere with drums, horns and singing.
Though Matildas' tickets will be at a premium, the team's presence in the knockout rounds will likely encourage more locals to take in other games as neutral fans.
Australia have never made it past the quarter-finals of a World Cup but the Matildas' players believe the crowd energy could help them go all the way to the final.
"We're just getting started," said Australia forward Caitlin Foord.
"We're already in the rhythm of it and we've just got to keep going, keep building on it now."