Cooper, whose enigmatic playmaking could turn a game either way, was lacklustre during the World Cup in New Zealand as the Wallabies adopted a conservative, territory-based game.
The 23-year-old was heavily criticised for his performances but the Queensland Reds fly-half, who suffered a knee injury in the third-place play-off that will keep him out of Super Rugby until at least April, said his free-spirited approach may have been stymied by coach Robbie Deans's tactics.
"I went out there and played the football I was allowed to play inside a gameplan," Cooper told Australian Associated Press.
"It might not have necessarily been the best gameplan.
"There was half the games that we didn't play very smart. Whether that was on the back of my shoulders, who knows?"
The Wallabies were outmuscled by Ireland in pool play and then New Zealand in the semi-finals before adopting a more expansive approach in the playoff for third place, where they beat Wales 21-18.
Deans had preferred to use his inside centre to run straight and take the ball into contact in an attempt to get over the gain line.
In the play-off, the New Zealander used the more creative Berrick Barnes at inside centre to act as a second playmaker, which contributed to the Wallabies' victory Cooper said.
"I think there was a time where we may have been over-thinking," Cooper added.
"Because when we came out in that game against Wales we basically said let's just go out there (and enjoy it).
"You can have all the words and all the motivational quotes and moves in the world but if you're not going out there and putting your heart and your mind into it with your team mates you're not going to play well.
"We just went out there and played some good football."