Despite a series of refereeing blunders which favoured the Africans, a goal by Mexico striker Oribe Peralta in the 61st minute condemned his side to a defeat in their opening encounter in Natal.
The loss leaves them in third place ahead of their opponents, Croatia, who sit on the bottom of the ladder on goal difference. Nevertheless, Finke is wary of the threat that Niko Kovac's men pose, and has rallied his troops to bounce back from a disappointing result.
"We must be ready to face the challenge," he said. "There were positives [in the last match]; we were able to create chances and played some good football.
"They [Croatia] have great players plying their trade in Spain and Germany and we must remain very cautious even if we both lost our first game. 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.
"It doesn't help to talk any more, we must just win to remain in the competition. When you lose the first match, you have to pick up maximum points to remain in the hunt."
However, their hopes of qualifying against the odds have been dealt a huge blow, with star striker Samuel Eto'o admitting that he will need "a miracle" for there to be any chance of him featuring against the Croats.
Despite playing against Mexico just days ago, the 33-year-old claims that he felt discomfort in his knee, and subsequently was unable to attend training. "I am hoping the gods grant me a miracle and that I am able to defend my dear, beautiful country," Eto'o admitted.