"We still have a lot of inconsistencies in our batting department," said Dhoni.
"Batting is supposed to be our strength, but it's been the middle order and the bowlers who have performed for us, so we need to click together better.
"Hopefully we can perform according to the potential we have in the side."
Dhoni indicated at the start of the tour that he may rest his fast bowlers towards the end of the ODI series, but said on Thursday that this would no longer happen.
"We need to play our fast bowlers. Zak [Zaheer Khan] must get back into the groove. The sub-continent can be very demanding and also quite humid, so we need him and the others to get used to the work rate.
"Harbhajan [Singh] is bowling as well as he has ever bowled throughout his career, and the part-timers are doing a good job for us, but we need our fast bowlers to be ready for the World Cup."
Constant drizzle on Thursday made life difficult for St George's groundsman Adrian Carter, who said it had been difficult preparing the wicket in the wet conditions while having to keep putting the covers back on.
"It's a good, flat batting wicket and the team batting first will need to score 260 to 280 runs on this ground to be competitive," he said.
"I'm just praying it doesn't rain tomorrow."
India lead the five-match series 2-1.