The Wallabies have lost to Wales for the first time since 2008 in a grinding 9-6 defeat in Cardiff.
It was the single-figure margin that spectators have come to expect from these two sides but for the first time in 14 matches it was the Dragons going home with the victory.
After an intensely tight, arm-wrestle of a game, the Wallabies turned down several kickable penalties to push for tries in the second half but eventually levelled scores at 6-all with six minutes on the clock courtesy of a Matt To'omua penalty.
But two mistakes from the kickoff saw Wales get the ball back and win a penalty in front of the sticks, with Ned Hanigan pinged for not rolling away.
Dan Biggar stepped up and nailed the penalty to take the match-winning lead.
The defeat was the Wallabies' eighth of an already demoralising year, and for Wales, victory served as a major psychological breakthrough given the two teams are in the same pool at the Rugby World Cup next year.
The Wallabies have now posted losses to all four home nations, including Ireland twice, in the past 12 months.
Cardiff saw a kind of performance Wallabies fans are becoming all too familiar with - some positive attack undone by simple errors and inconsistency across the board.
When they had the ball, the Wallabies struggled to make major gains and when they broke the line, they were often unravelled by a knock-on or the Welsh defence.
Often aimless tactical kicking didn't help Australia much either, giving Wales the opportunity to run back at them or win the territory battle via the boot.
Wales were guilty of their own mistakes as well, in another edition of tight Cardiff affairs between the two nations.
A rapid fire start It nearly paid off for the Wallabies in the fourth minute but Samu Kerevi was forced into a knock-on just shy of the line.
It wasn’t all just running rugby - flyhalf Bernard Foley put up a high bomb in one attacking push, with the target clearly Israel Folau bu the winger couldn’t get near it.
Wales tried their own tricky kick, a grubber through to Josh Adams but their speedster couldn’t collect it before it made touch.
Scrums quickly became an issue for the Wallabies, losing two in a row and Halfpenny made them pay despite an uncharacteristically patchy night from he Welsh kicker.
A 16-phase attacking push from the Wallabies ended with a cold knock-on from lock Adam Coleman and another scrum penalty undid the side’s patience.
Bernard Foley finally drew blood for the Aussies with a 33rd-minute penalty after two Welsh defenders were caught offside and the 3-3 score remained until half-time.
It was Wales with all the attacking ball early in the second, led by an electric Halfpenny, and though the Wallabies’ defence managed to hold them out,
Wallabies captain Michael Hooper made it clear he backed his side to score a try in the second half, opting twice for a lineout over kickable three-pointers.
The first chance was snuffed out by a Wallabies knock-on and on the second an overthrow opened the door for Wales to pounce in attack.
Wallabies coach Michael Cheika injected front rowers Taniela Tupou and Tatafu Polota-Nau in the 55th minute and it paid immediate dividends with the Wallabies pushing Wales backwards in their first scrum of the afternoon.
When Wales had a chance for three, Alun Wyn Jones took no time in pointing to the sticks when hooker Tatafu Polota-Nau was pinged at the breakdown.
Halfpenny took no time vindicating his skipper’s choice to give Wales the lead with 12 minutes left.
When Kurtley Beale spilled a high ball in the 73rd minute, the Welsh crowd could almost taste a match-winning try but the Wallabies cleaned up their own mess.
A Samu Kerevi hit on Halfpenny ignited the crowd again, with the Wallabies centre attempting a charge down on the fullback’s kick before appearing to collect him high.
It was the Wallabies who soon won a penalty, kicked by To'omua, but they returned the favour two minutes later with Dan Biggar slotting the match-winner.
The Wallabies head to Italy on Monday morning (AEDT) ahead of their second November Test.
Pens: Halfpenny 2, Biggar
Pens: Foley, Toomua