As expected, the only changes to the team that completed a three-Test June whitewash of Wales were forced by injuries to centre Pat McCabe and No.8 Wycliff Palu.
Anthony Faingaa replaced McCabe, while Dave Dennis was brought in at blindside flanker, with Scott Higginbotham shifting from that position to No.8.
Cooper has played five Super Rugby games and some club games in Brisbane since returning from knee surgery after being injured in last year's World Cup bronze medal game.
Deans revealed settling on his five-eighth hadn't been a particularly difficult decision.
"Berrick played very well through June and we had good continuity prior to the mishap with Pat McCabe, so it was pretty straightforward," Deans told reporters.
Deans said Cooper took the news of his omission very well.
Asked what the mercurial Reds back needed to do to regain a spot, Deans said "keep doing what he's doing - keep working with us.
"There's not a lot of certainty in this industry.
"I've got no doubt he'll get an opportunity again, absolutely."
Regarding Faingaa's selection, Deans said the Queensland back's history with the group was the factor that earned him the contentious position.
"He's been a big part of this 22 for quite a while now and he's had quite an impact," Deans said.
Barnes and Faingaa have little experience as a 10-12 combination.
"I've played a lot more in the centres with Ant - 12 and 13. I haven't played a lot of 10 and 12 with him," Barnes said.
Deans said Dennis, who will make just his second Test start, had proven himself as an international player in the June Tests.
"He's been great - he's very consistent," Deans said of Dennis.
Wallabies: Kurtley Beale, Adam Ashley-Cooper, Rob Horne, Anthony Faingaa, Digby Ioane, Berrick Barnes, Will Genia, Scott Higginbotham, David Pocock (capt), Dave Dennis, Nathan Sharpe, Sitaleki Timani, Sekope Kepu, Tatafu Polota Nau, Benn Robinson. Res: Stephen Moore, James Slipper, Rob Simmons, Radike Samo, Michael Hooper, Nick Phipps, Drew Mitchell