There was no disguising the pain after the Wallabies had their once-in-a-lifetime grand slam dream shattered in the cruellest fashion in Dublin on Sunday (Monday AEDT).

The Wallabies were devastated after Ireland's record-setting captain Brian O'Driscoll steamed over for a last-minute try to snatch a dramatic 20-all draw for the Six Nations champions at Croke Park.

"We felt we had it there, certainly to keep the grand slam alive, but obviously the grand slam is dead. You don't really know what to feel," stunned five-eighth Matt Giteau said.

Australia have been left exasperated, frustrated, humiliated, demoralised and plain filthy by some of their more recent losses, but this was truly their most deflating defeat since the 2007 World Cup quarter-final shocker against England in Marseilles.

Never has Robbie Deans been more dejected during his 26-Test coaching reign after watching his brave Wallabies fall agonisingly short of halting rampant Ireland's eight-Test, 12-month winning streak.

"It was a gutsy effort in terms of dominating the game but, once again, we didn't get the reward and we're certainly not getting the rub of the green, that's for sure," Deans said after the Wallabies once again suffered at the hands of the referee.

In a harsh decision that had Australian fans chanting "bullshit, bullshit", South African official Jonathan Kaplan sin-binned Wallabies No.8 Wycliff Palu in the first half for a supposed no-arms tackle on Ireland fullback Robert Kearney.

Deans felt it was a "magnificent" hit from Palu, while Kaplan also awarded Ireland a series of other baffling penalties but, most critically, denied Australia one which they felt they deserved for destabilising Ireland's scrum in the lead-up to O'Driscoll's try.

Australia were never headed and seemed set for victory when inspired captain Rocky Elsom, in his first appearance in Dublin since leading Leinster to European Cup glory six months ago, charged over in the 62nd minute to give the Wallabies a 20-13 advantage.

Elsom's try - which followed winger Drew Mitchell's in the second minute after he punished O'Driscoll's knock-on with his first touch of the ball in his 100th Test - was just reward after the Wallabies repeatedly punched holes in the Irish defence.

Giteau, Palu, Elsom, fullback Adam Ashley-Cooper and official man-of-the-match David Pocock, who vindicated his selection at openside flanker ahead of 107-Test stalwart George Smith with a barnstorming display, all broke clear as Ireland battled to hang on.

Even Ireland coach Declan Kidney conceded the hosts were fortunate.

"I suppose you could say we escaped," he said.

"Australia played a good game. They put us under a lot of pressure. We were never on the front foot.

"It seemed to me that we played a large chunk of the game in our own half, that they won the field-position battles."

Australia's once-maligned scrum was also dominant but, for all their toil, the Wallabies were unable to ever kick clear and spent most of the final quarter under siege defending their line.

Winger Tommy Bowe, who scored Ireland's first try in the 56th minute to lock the game up at 13-13, after Australia led 10-6 at halftime, was held up over the line by four desperate Australians in the play immediately before O'Driscoll's last-gasp effort.

Given his knack for scoring on the biggest occasions, it was almost inevitable O'Driscoll would eventually strike.

And he did so off a brilliantly worked move, with decoys so confusing the Wallabies' inexperienced midfield that he crossed untouched.

But it still crushed the Wallabies, the stalemate taking the fizz out of the rest of the tour with no prospect of Deans's young side emulating Australia's legendary 1984 grand slammers who completed a sweep of wins over England, Ireland, Scotland and Wales.

"That was the carrot coming over here and what we were after," Pocock said.

Instead the Wallabies will head to Edinburgh on Monday with the humble aim of finishing the European section of their tour unbeaten with victories over Scotland and then Wales in Cardiff on Saturday week.

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