The Europeans were forced to play on the counter-attack against hosts Brazil in the tournament opener, eventually going down 3-1 despite taking an 11th-minute lead.
Kovac was disappointed with a number of decisions in that game, including a controversial penalty for a challenge on striker Fred, but he is now focused on the second Group A clash and is confident that his side can assert themselves on the game on Wednesday.
"I think a rest day is always useful. Everyone has recovered and today we will train," he said at a press conference on Sunday.
"Against Cameroon it will be a completely different game. It was difficult to attack Brazil, we had to look through counter-attacks, but against Cameroon we will have greater ball possession and seek dominance.
"The first goal will be an advantage, it would be good to go in to half-time with a positive result.
"We know all about Cameroon, we analysed them like Brazil and will set our tactics accordingly.
"Our goal is to take the three points, and this is a game with growing importance."
