Kevin Pietersen gives backing to skipper Alastair Cook

Kevin Pietersen has said Alastair Cook has his backing despite a shaky start to his time as England one-day skipper.

England trail 2-1 with two to play in their series against Sri Lanka going into Wednesday's match at Trent Bridge.

Pietersen said: "Cooky is in charge [and] it's vital that whatever decisions he makes, we back. That's got to be good for his confidence.

"To become a successful and confident captain, you want to have the backing of your players."

Cook began his tenure as Andrew Strauss's successor with a 110-run Duckworth-Lewis victory over Sri Lanka at The Oval.

But consecutive defeats have followed, by significant margins, at Headingley and Lord's.

Critics have questioned Cook's suitability as an ODI opening batsman - notwithstanding his century at Lord's on Sunday - with some insisting he and Jonathan Trott cannot co-exist in the same 50-over team at one and three in the batting order.

Their measured styles put the onus on the likes of number four Pietersen, Cook's fellow opener Craig Kieswetter and Eoin Morgan to score quickly.

But former England captain Pietersen said: "I have kept well out of it.

"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'.

"Decisions have to be made. I don't make any decisions; I'm one of the soldiers.

"I'm just happy to be playing and I want to be doing my own role better."

Despite Cook's second ODI century at Lord's, England could not amass a defendable total.

"We just haven't been consistent in these last two games," Pietersen commented. "We have been outplayed by a better team.

"We outplayed them at The Oval and that's where we want to get back to. We all have to deliver.

"I just think there are a lot of things we can all improve on. We all need to fulfil our roles like we did at The Oval. If we all play like that, we win."

Pietersen, who has recorded just one 50 in his last 12 ODI outings, accepts he has a responsibility to contribute more.

"I'm getting to 30-40 in that aggressive way and not kicking on," he added. "I just need to concentrate on what I'm doing and getting my stuff right."