Mahendra Singh Dhoni admits India's one-day side are not at their best ahead of Friday's Tri-Series decider against England.

Whichever side wins at the WACA will go on to meet Australia in the the final 48 hours later, while the losers head into World Cup month on a low note.

The ODI rankings favour Dhoni's men, who are second to England's fifth, but that counted for little when the teams met in Brisbane last week.

A springy Gabba deck played into England's hands as India collapsed for 153 en route to a nine-wicket thrashing.

And captain Dhoni recognises the need for an improved showing.

"I'm not really (satisfied), but it doesn't always go as planned," he said.

"I have been in this position quite a few times. We know what needs to be done and ultimately what's important is for the guys to take that extra responsibility because you just need that spark, that 10-15 minutes and everything falls back into the right place."

Rohit Sharma, India's big-hitting batsman, will again be missing as he recovers from a hamstring injury, placing further spotlight on the mis-firing batting order.

Star man Virat Kohli's continued deployment at number four and a perceived lack of firepower lower down the order have both been criticised and Dhoni has his own concerns about the line-up.

"The reason why Virat is batting at number four is the strength of the middle order and the lower middle order," Dhoni said.

"In the middle order we have lost too many wickets and that really hampers the plan because if you get off to a good start and you have a good partnership then you don't want wickets to fall in pairs.

"That is what is happening to us so if we can avoid that then everything will be good.

"If I am batting at six and I am worrying about the batsmen coming after me, whether they can or cannot play eight to 10 overs... if I look to play a big shot and if I get out, whether we will be able to capitalise or not... that's the reason why Virat has to bat four."

Dhoni went on to query England's apparent edge over India, suggesting the previous result and the nature of the Perth pitch would not be factors.

"They had the psychological advantage in the ODIs last year in England as well (when India won the series)," he said with a smile.

"And in Perth is not like the ball comes off 15 or 20kmph faster. Whoever bowls 140kmph bowls only 140kmph."