A last-gasp penalty from fly-half Greig Laidlaw on Tuesday night gave Scotland, ranked 12th in the world, a second successive win over the second-ranked Australians and condemned the Wallabies to a losing start for the second year in a row.
The gale-force winds and rain battering the Hunter Stadium were one factor clearly beyond Deans's control, while the scheduling of a match just three days after the end of the last Super Rugby round, and four days before the series against Wales begins, was not his call.
Missing three of Australia's most potent backline threats in James O'Connor, Kurtley Beale and Quade Cooper did not help either, but Deans still faced headlines in Wednesday's newspapers which placed the blame squarely on his own shoulders.
Deans always accepts injuries as part of the game, however, and was clearly more concerned, and irritated, by his team's inability to make the most of their opportunities to close the game out.
"Obviously it was a challenging week prior to the conditions, if you like, but it was still there to do," he said after the match.
"Conditions affected the game, no doubt, whether it was a leveller is a moot point, everyone will have their opinion on that, but it clearly affected the contest," he added.
"As tends to happen in conditions like that, when you don't turn the scoreboard over, it gets messier as the game goes on, the opposition grows a leg if you give them that encouragement and anxiety kicks in ...
"Compounding factors and we lacked the coordination to work our way out of it."
Australia rebounded from a similar upset at the hands of Samoa in Sydney last year to win the truncated Tri-Nations and finish third at the World Cup.
Deans will be hoping for a similar response from his players this year, starting in the first of three Tests against Six Nations champions Wales in Brisbane on Saturday.
"It's a similar circumstance, something good came out of that so that'll be our intention in this instance," he said.
"We've got another Test match on Saturday and first thing we've got to do is recover, check the state of the blokes, select a combination and try and get some sort of preparation for the next one."
Deans was not prepared to take the blame for the decision to squeeze a fixture against Scotland into an already crowded calendar, as a favour to the Scots and not for revenue generation according to the Australian Rugby Union.
"Those decisions are made further up the food chain," he said.
Still, in praising the performance of flanker Dave Dennis, who played for the New South Wales Waratahs in Super Rugby last Saturday, Deans betrayed that he was perhaps less than enthusiastic about the scheduling.
"Dave has got the chance to play three games in seven days ...," he laughed.
Dennis was one of six Australians along with full-back Luke Morahan, winger Joe Tomane, centre Mike Harris, prop Dan Palmer and flanker Michael Hooper to win their first caps in something of a baptism of fire on Tuesday.
"They'll never forget it, for many reasons, they're on their way," Deans said.