Australia coach Robbie Deans believes Saturday's Twickenham showdown with England will be the toughest assignment of their autumn tour.

The Wallabies have been installed as odds-on favourites to retain the Cook Cup against a makeshift England side hampered by a chaotic build-up.

The fact Australia are packed full of unfamiliar names themselves underlines the problems facing Martin Johnson's side in the eyes of bookmakers.

But even with Grand Slam champions Ireland up next, Deans has identified England as the greatest threat to their ambition to topple all four home nations.

The Wallabies coach said: "Saturday is the toughest game because it's England at Twickenham - that's the way it is.

"We'll have to earn everything we get. We've prepared to win the match and that's what we're aspiring to do.

"England will expect to win and we have an opportunity to chase that result, but we're presuming nothing.

"I wasn't aware that we're favourites and frankly it doesn't interest me.

"There's no balance to be struck between rebuilding and winning - we want to do well on Saturday.

"Our squad isn't experienced but we've selected the team to do well on the weekend.

"It's not as though we've left a lot at home. This is our best crew, England have selected their best crew."

Deans was happy to discuss Jonny Wilkinson's Test comeback earlier in the week, describing it as "critical" to England, and at today's team announcement he revisited the theme.

This time he stressed the importance of Australia's pack cutting off the Toulon fly-half's ability to make an impact at source.

"Jonny's return makes it distinct from the contest we had here this time last year," said Deans, who watched his Wallabies triumph 28-14 at Twickenham 12 months ago.

"He can be influential and we want to minimise that as best we can. A big part of that will come from the foundation laid up front."

The team unveiled by Deans may be short on stardust but skipper Rocky Elsom is one player well-known to the northern hemisphere.

Elsom captured the imagination during last season's Heineken Cup when a string of Herculean displays in the knockout stages helped Leinster seize their first European crown.

The wrecking-ball back row left Ireland to re-sign for the Australian Rugby Union during the summer and instantly became a key member of the squad.

"Rocky is an influential character. He's a strong man with a strong mind and is a good bloke to have alongside you," said Deans.

"His team-mates feed off that. He doesn't like to give ground and has the ability to inspire until the end.

"The captaincy is a new experience for him but he's taken to it pretty well.

"He hasn't tried to be something he's not, he's just kept doing what he does.

"We don't want him to call all the shots because he has a C beside his name."

Elsom, fly-half Matt Giteau and recalled openside George Smith are the senior figures in an Australia line-up every bit as makeshift as England's.

In total the tourists have made five changes, two positional, from the team that lost 32-19 to New Zealand in last Saturday's Bledisloe Cup clash in Tokyo.

Smith wins his 107th cap at the expense of David Pocock, who drops to the bench, while a new-look partnership of Digby Ioane and Quade Cooper have been selected in midfield.

Both have limited experience at centre - Ioane has played most of his rugby as a winger while Cooper scored 16 points at fly-half in Tuesday's 36-5 win over Gloucester.

Teams:

England: U Monye (Harlequins); M Cueto (Sale Sharks), D Hipkiss (Leicester), S Geraghty (Northampton), M Banahan (Bath); J Wilkinson (Toulon), D Care (Harlequins); T Payne (Wasps), S Thompson (Brive), D Wilson (Bath), L Deacon (Leicester), S Borthwick (Saracens, capt), T Croft (Leicester), L Moody (Leicester), J Crane (Leicester).

Replacements: D Hartley (Northampton), D Bell (Bath), C Lawes (Northampton), J Haskell (Stade Francais), P Hodgson (London Irish), A Goode (Brive), A Erinle (Biarritz).

Australia: A Ashley-Cooper (Brumbies); P Hynes, D Ioane, Q Cooper (all Queensland Reds), D Mitchell (New South Wales Waratahs); M Giteau (Brumbies), W Genia (Queensland Reds); B Robinson (New South Wales Waratahs), S Moore, B Alexander (both Brumbies), J Horwill (Queensland Reds), M Chisholm, R Elsom (capt), G Smith (all Brumbies), W Palu (New South Wales Waratahs).

Replacements: T Polota-Nau (New South Wales Waratahs), M Dunning (Western Force), D Mumm (New South Wales Waratahs), D Pocock (Western Force), L Burgess (New South Wales Waratahs), R Cross, J O'Connor (both Western Force).

Referee: Bryce Lawrence (New Zealand).

Assistant referees: Nigel Owens and Tim Hayes (both Wales).