Rookie Quade Cooper is under express orders not to overplay his hand after being thrown into the hot seat for the Wallabies' most significant match of Robbie Deans's 25-Test coaching reign.

Deans' daring selection of the mercurial Cooper and the explosive Digby Ioane as an untried Test centre pairing for Saturday's high-stakes encounter with injury-hit England has added another intriguing edge to the Wallabies's grand slam tour opener.

With six defeats in their past seven Tests, the Wallabies are battling to avoid their most barren run since Eddie Jones was sacked as coach after presiding over one solitary win from nine matches in late 2005.

While Deans's position seems secure, fickle fans will be quick to the trigger if his selection gamble backfires and the Wallabies's grand slam hopes evaporate at the hands of the weakest England team to grace Twickenham in years.

Deans, though, has every faith in his new-look midfield, saying Cooper commanded a second Test start after his "coming-of-age" display in Tuesday's big win over Gloucester and that Ioane confirmed in his eye-catching comeback game on the wing against New Zealand last week that he needed to be closer to the action.

Often criticised as erratic and careless, Deans believes 21-year-old Cooper has blossomed into a responsible playmaker worthy of a chance to direct the Australian backline in tandem with midfield general Matt Giteau.

"Gits will be calling the shots obviously and he'll direct it the way he sees fit but I think you will see both players in both roles," Deans said, freeing up Cooper to step into flyhalf at stages, just as it was planned Berrick Barnes would before breaking down in Tokyo.

Cooper is aware, though, that his attacking licence has restrictions, with Deans warning him of the perils that his signature wide passing game can bring.

"England will look to feed off those," Deans said.

"He's got a passing game, just as he's got a kicking game.

"He'll be pretty clear in his own mind what his role will be. The message will simply be 'enjoy'.

"(But) making decisions to serve the team is pretty important in those servant roles, because that's what they are. If you chase your own interests all the time, it can hurt."

With Stirling Mortlock set to join the squad in Dublin on Sunday, and available for Australia's next Test against Ireland after recovering from a calf injury, Ioane is also eager to make the most of his opportunity.

Ioane confessed to knowing little about England's centre pairing, with the hosts fielding a backline of mostly Test rookies - with the exception of World Cup-winning five-eighth Jonny Wilkinson.

But having Wilkinson back in the mix after 18 months in the international wilderness is enough to have the Wallabies on guard against complacency.

"There's nothing in it at this level. You can't take anything for granted. The moment you do, it bites you," Deans said.

"France have been south (to Australia and New Zealand) this year and beaten the All Blacks. We managed to beat France at home.

"England were up 29-0 over them at halftime (in this year's Six Nations). England are playing at home on the weekend. They will expect to win.

"We've got an opportunity to chase a result and we're pretty excited about that, but we're presuming nothing."

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