India sealed an 80-run win over West Indies in the concluding group match of the tournament in Chennai on Sunday, but only after a spectacular collapse by the brittle Caribbean side, who crashed from 154-2 to 188 all out.
While India will tackle Australia in Ahmedabad on Thursday, the West Indies take on in-form Pakistan in Dhaka on Wednesday in the opening quarter-final tie.
"We will be at our best for the quarter-finals," said Dhoni.
"Australia are a very strong side and very expressive on the field. But it's about how we prepare for the game to achieve what we want.
"In the process, we hope to give our best."
Dhoni praised strike bowler Zaheer Khan, whose three wickets included the key dismissal of opener Devon Smith who had made 81 when he was clean-bowled, a wicket which precipitated the West Indies collapse.
"He changed the game. He got the breakthrough by getting rid of Smith. Once we got his wicket, we were able to put pressure on all the batsmen at both ends."
All-rounder Yuvraj Singh was man of the match for his 113 runs and 2-18 with the ball.
Yuvraj overcame illness to help his team to victory and doubled-up in pain during his innings.
"I had stomach cramps and I was struggling in the morning but I was just worried about the match and the team," said Yuvraj.
Zaheer praised his team's tactics which saw the new ball tossed to spinner Ravichandran Ashwin.
"We knew that with the new ball it would come on to the bat and that the seamers would get reverse swing later on in the innings, so that's why we used a spinner to open the bowling," said Zaheer, who took 3-26.
