But they never stopped believing - or tackling. The Australian team is stacked full of stars but looked bereft of ideas by the end, worn down by the Kiwis’ defensive line that refused to break.
New Zealand were the better team in the second half, with Leianne Tufuga’s 74th-minute try breaking a 6-6 deadlock to cap an unforgettable victory, their first over Australia since 2016.
There were heroes across the park for Ricky Henry’s young side, who have improved across markedly across the Pacific Championships.
The match was won in a bizarre first half.
The Kiwi Ferns defended with remarkable resilience but were also cruelly plagued by constant errors. If there was a way to make a mistake they found it, from making a mess of the kickoff, being pushed over the sideline or fumbling a play the ball, which invited constant pressure.
Jillaroos winger Jamie Chapman opened the scoring in the 10th minute after the Ferns were caught short on the right edge. It was a disappointing concession - as the defenders got their numbers wrong - though Tarryn Aitken’s cut-out ball showed great vision.
It felt like that was going to be the start of a flood of points, as the home side set up camp in New Zealand territory, but it didn’t happen. The Ferns somehow hung on, thanks to some desperate last-ditch defending.
Fullback Apii Nicholls epitomised the effort, forcing a mistake from Tamika Upton as she looked certain to score, with the ball dislodged just before the line.
New Zealand had limited first-half opportunities. An early 40-20 kick by McGregor gave rare territory but that was followed by an unconvincing set, while another attacking chance - following a penalty - was spoilt by an error.
But the Ferns were finally rewarded for their grit and effort just before halftime, with Hufanga powering over off an inside ball after Tiana Davison had managed a one-on-one steal near halfway.
The New Zealand side thought they had gone ahead through a cracking Nicholls try early in the second half - after they attacked coast to coast - but it was scratched by the bunker with a frustrating obstruction call. It was a tenuous judgement, as Ali Briggenshaw looked to be barely disadvantaged, if at all, before she missed the tackle on the Ferns fullback.
That was compounded soon afterwards when they lost playmaker and chief kicker McGregor to a 15-minute HIA assessment. But the Ferns kept defying the odds, with a series of defensive sets on their line, epitomised by the three-person tackle to hold Jakiya Whitfeld up.
They had another huge setback, losing Hufanga for the final 14 minutes to an HIA check after the centre copped a knee to the head following a breakaway. But they didn’t relent, before a magic Nicholls ball sent Tufuga across in the corner, with McGregor’s conversion bouncing over off the crossbar to ice the moment.
Kiwi Ferns 12 (Mele Hufanga, Leianne Tufuga tries; Raecene McGregor 2 cons)
Jillaroos 6 (Jamie Chapman try; Lauren Brown con)
HT: 6-6