Replacement Mike Harris slotted a penalty deep into injury time to give Australian a 25-23 win and an unassailable two-nil series lead over Wales in Melbourne on Saturday.
The lead changed hands several times in a thrilling second half - as Berrick Barnes and Leigh Halfpenny exchanged kicks at goal.
With time up on the clock, the Wallabies earned a penalty, set a maul and won another penalty. Harris, who had come on in the 72nd minute for Berrick Barnes, who struggled with severe cramps, stepped up to slot the winner in front of 33,888 delirious fans.
They simply don't come any closer than that!
Wallabies flyhalf and new dad, Berrick Barnes, played a vital role in helping his side over the line - setting up the Wallabies only try, in injury time of the first half and scoring 17-points off his own boot.
In a game that saw the lead change hands nine times it wasn't until after the siren that game was finally decided.
As was the case in the first half Wales crossed first, in the 43rd minute, to recapture the lead the Wallabies had snatched from them in the dying stages of the first half.
The Wallabies hit back through the boot of Barnes just five minutes later and as the half continued both sides traded penalty goals.
With Wales ahead by a single point with just seven minutes to play Barnes had the chance to put the Wallabies ahead, however he couldn't convert the penalty goal attempt giving hope to the Welsh fans and players.
Just minutes later the Wallabies won a penalty inside their own half and after a successful line-out, won a penalty from the ensuing maul.
With Berrick Barnes substituted minutes before and the final siren having sounded seconds before Mike Harris stepped up to take the winning penalty goal attempt.
The gold coloured crowd behind the goals told the story as Harris kicked truly to give the Wallabies a series winning victory.
Man of the Match: Leigh Halfpenny and Jonathan Davies were above average among the Welsh backs, while Dan Lydiate, Alun Wyn Jones and Gethin Jenkins (before a late scrum penalty) were the best forwards for the visitors. However, new dad Berrick Barnes - who flew from Melbourne to Sydney on Friday for the birth of his first child and arrived back in Melbourne on Saturday just two hours before kick-off - produced a sublime performance. He controlled the match perfectly and set up Australia's only try with a great break. Cramping eventually got the better of the high flyer, but Barnes wins our award.
Moment of the Match: There was that moment of magic from Barnes right on the half-time break that resulted in a try for Rob Horne, while Jonathan Davies got an equally crucial try two minutes into the second half. But you simply can't beat Mike Harris's injury time match-winning penalty.
Villain of the Match: No doubt it goes to Cooper Vuna for his moment of madness - an air tackle on Leigh Halfpenny that earned him 10 minutes in the bin.
Pens: Barnes 5, Harris
Tries: North, Davies
Cons: Halfpenny 2
Pens: Halfpenny 3
Yellow card: Cooper Vuna (Australia, 60 - foul play, tackling Leigh Halfpenny in the air)
Australia: 15 Adam Ashley-Cooper, 14 Cooper Vuna, 13 Rob Horne, 12 Pat McCabe, 11 Digby Ioane, 10 Berrick Barnes, 9 Will Genia, 8 Wycliff Palu, 7 David Pocock (captain), 6 Scott Higginbotham, 5 Nathan Sharpe, 4 Rob Simmons, 3 Sekope Kepu, 2 Tatafu Polota-Nau, 1 Benn Robinson.
Replacements: Stephen Moore, 17 Ben Alexander, 18 Dave Dennis, 19 Michael Hooper, 20 Nic White, 21 Anthony Fainga'a, 22 Mike Harris.
Wales: 15 Leigh Halfpenny, 14 Alex Cuthbert, 13 Jonathan Davies, 12 Ashley Beck, 11 George North, 10 Rhys Priestland, 9 Mike Phillips, 8 Ryan Jones, 7 Sam Warburton (captain), 6 Dan Lydiate, 5 Alun Wyn Jones, 4 Bradley Davies, 3 Adam Jones, 2 Matthew Rees, 1 Gethin Jenkins.
Replacements: 16 Richard Hibbard, 17 Paul James, 18 Luke Charteris, 19 Justin Tipuric, 20 Rhys Webb, 21 James Hook, 22 Scott Williams.
Referee: Chris Pollock (New Zealand)
Assistant referees: Craig Joubert (South Africa), Garratt Williamson (New Zealand)
TMO: Vinny Munro (New Zealand)