Kevin Pietersen gets behind fledgling captain Alastair Cook

Alastair Cook can count on Kevin Pietersen's unqualified support from the ranks, as the novice captain tries to put his stamp on England's new 50-over era.

Cook began his full-time tenure as Andrew Strauss' post-World Cup successor with a heartening 110-run Duckworth-Lewis victory over Sri Lanka at The Oval. But consecutive defeats have followed, by significant margins, at Headingley and Lord's, meaning Cook's England trail in the NatWest Series 2-1 with two to play, starting at Trent Bridge tomorrow.

Critics of the new regime have been quick off the mark, questioning already Cook's own suitability as a one-day international opener - notwithstanding his century at HQ on Sunday - and the effectiveness of the personnel under him, with both bat and ball.

Former captain Pietersen appears well aware it would be all too easy, and unhelpful, if he overdid the advice for England's new leader, either privately, or publicly.

"As soon as a new captain takes over, it is everybody's responsibility to back off and not get involved," he said. "The last thing you want as captain is everybody telling you you are not doing the right thing, or you are doing the right thing. Not everybody is right. You have to back the captain. To become a successful and confident captain, you want to have the backing of your players. I give Cooky my sole backing."

Pietersen's own reign was notably brief, between August 2008 and January 2009, before apparently irreconcilable differences between himself and coach Peter Moores spelled the end of the line for both in those roles.

After just three matches of the Cook era, some are insisting he and Jonathan Trott cannot co-exist in the same 50-over team at numbers one and three because they do not play enough big shots for the modern game.

Their accumulative styles put the onus on the likes of No 4 Pietersen - along with Cook's opening partner Craig Kieswetter and Eoin Morgan - to find and clear the ropes.

A modified batting order is one of the remedies being prescribed. But Pietersen said: "I have kept well out of it. It has nothing to do with me.

"Cook is a new captain, and the last thing you want to be doing is putting yourself out there saying 'This is what we need to do'.

"Cooky is in charge. He played beautifully on Sunday for his hundred. It's vital that whatever decisions he makes, we back, instead of questioning them.

"That's got to be good for his confidence."