Ravaged by injury, hammered by the media and seemingly at odds with each other within the squad, they came through to clinch a 25-19 win over the Pumas in Rosario to confound their critics.
Deans had a Test team of injured players watching back home, including three captains, while Nathan Sharpe led his side to an against-all-the-odds triumph in his 111th outing in green and gold.
That is the kind of defiance the Wallabies had shown in beating Grand Slam champions Wales 3-0 in June and why, with a clean bill of health, they will be a major threat to Warren Gatland's Lions side on their 125th anniversary tour next summer.
Sharpe moved into second place on the Australian all-time cap list behind George Gregan, and overtook Geroge Smith as Australia's most capped forward, in his side's third victory in the championship. It was also a win, coupled with the All Blacks' triumph over the Springboks, that moved them back into second place in the IRB World Rankings.
No wonder than that Deans rated the rousing Rosario performance as "one of the gutsiest and most satisfying" of his reign as Wallaby coach.
''I'm proud of the group. I think we saw evidence of the meaning to this group," said Deans.
"We've experienced a fair amount of adversity, but we'll get the benefit of this time. One of our focal points was not to let the crowd in, particularly early on.
''They silenced the crowd early and didn't allow the Pumas to get a leg-up. It's a fantastic experience for these blokes - it was genuine old-school.''
Deans now has the small matter of a final Bledisloe Cup clash with New Zealand to attend to before he heads 'North' for the four test, spring tour of Europe. The Wallabies play France, Italy, England and Wales.
They will be looking to pick up a sixth win in 13 months over Wales when they meet at the Millennium Stadium on December 1, while England will be aiming for a third win in a row over the Wallabies.