The Kookaburras' once vice-like grip on Olympic gold is suddenly looking vulnerable, and predictably it's Great Britain shaking the tree.
Yet another example of the host nation performing out of its skin at the Games was on display as Great Britain fought back from 3-0 down to draw 3-3 with the world No.1 men's hockey team on Sunday.
It means Australia have been pitched into a four-team dogfight to get out of a pool most expected they would strut through on their way to the medal rounds.
They still sit on top of Pool A with two wins, two draws and a healthy goal difference.
And the Kookaburras need only a draw against Pakistan in their final group game on Tuesday to guarantee a top two spot and a semi-final place.
But two successive draws - both after conceding good leads and dominant first halves - suddenly offers hope to Great Britain, Pakistan and Spain, who could all advance at Australia's expense with wins on Tuesday.
Great Britain, on equal points with Australia, take on Spain, who scored three goals in the final few minutes to beat Argentina 3-1 on Sunday.
The Spaniards now sit equal with Pakistan, one point behind the current top two.
Certainly the Kookaburras aren't panicking, saying they have the toughness and work ethic to fix their problems as coach Ric Charlesworth vows to tighten up a defence which has shipped five goals in two games.
"There are ups and downs in tournaments. If you want to get out the other side, you have to weather them," he said.
And experienced co-captain Mark Knowles says the Kookaburras are up for the fight.
"We know what we have to work on ... it does put us in a tough situation, but it's the Olympics. You don't expect an easy ride."
The Kookaburras looked to be cruising to victory against the Britons, leading 3-0 six minutes into the second half through two first-half Russell Ford goals and one to Knowles just after the break.
Roared on by a capacity Riverbank Arena crowd, Great Britain came storming back.
First Jonty Clarke's dribble down the right found the net with a deflection off Australian defender Liam De Young's stick on 47 minutes.
Then skipper Barry Middleton added a second seven minutes later, getting a stick on a beautifully worked penalty corner to make it 3-2.
The brave Britons deservedly pinched an equaliser with four minutes remaining when James Tindall hammered home against a 10-man Australia, who were minus Knowles at the time because of a green card suspension.