After opening-round defeats, Cameroon face Croatia with both teams needing a win to keep their dreams of reaching the last 16 alive.
Volker Finke saw his Cameroon side fall to a 1-0 setback to Mexico last Friday, despite having what appeared to be a valid goal disallowed by offside.
The African nation, who have now lost their last five games at the finals, were left frustrated and know the Croatia clash in Manaus holds the key to their hopes of progressing in Brazil.
With the tournament hosts last up in Group A for Cameroon, Finke has stressed the significance of Wednesday's game, but the 66-year-old will not be panicked into wholesale changes to secure a win.
"When you lose the first match, you have to pick up maximum points in the second to remain in the hunt," he told FIFA.com.
"It's obvious that we need to change something, but in football, the worst thing you can do is call everything into question.
"That doesn't work. In my opinion, you can't succeed like that. Doubts will drive you crazy.
"They lead to other doubts and you can't perform well when you start having doubts.
"That doesn't mean you shouldn't go in for self-criticism, but doubt brings in question the very foundation of football, which is cooperation."
Croatia find themselves bottom of the group after the 3-1 defeat to Brazil in the opening match of the 2014 showpiece, meaning the side ranked 18th in the world will be wary of the need to improve their goal difference.
Coach Niko Kovac watched Italy's 2-1 win over England in Group D on Saturday closely to understand how the conditions at the Arena Amazonia will affect his players.
Kovac wants his side to seize the initiative and is well aware of the importance of a making a quick impact before the humid conditions take a toll.
"We have seen that after 70 minutes (in Manaus) players started to shut down," he said. "That game (England v Italy) was good and showed we cannot keep up the pace from start to finish.
"Who has the ball, dictating the pace (will benefit) and who is chasing the ball will lose energy.
"The first goal will be an advantage, it would be good to go in half (half-time) with a positive result."
Croatia have been buoyed by the news that midfield playmaker Luka Modric is likely to start, despite a knock after the Brazil game.
However, things look bleaker for Cameroon striker Samuel Eto'o, who is a major doubt with a knee injury.comments