Both sides have been stuck in the bottom three since the start of the season, but a win for either could take them out of the relegation zone for the first time.
With that in mind, Cosmi wants his players, especially those who returned from 10 days on international duty, to rise to the occasion and seize the opportunity.
"I don't think there are any doubts for anybody about how important this game is," he said.
"I have faith in the lads; in their intelligence. I know that we will be attentive and have the necessary concentration, with the right focus and serenity, because that is important too."
Cosmi is contemplating a tactical change for the trip to Bergamo with Daniele Mannini moved into a support role behind Emanuele Calaio.
"If he is mentally and physically sound, then that is the position in which he is able to express himself the best," explained Cosmi at the pre-match press conference.
"Thanks to his physical strength, he has the chance to be the right man to open up the games for us.
"When he plays out wide, he has more defensive tasks to do. This way, he can get himself in front of goal, which is sometimes what he lacks."
One thing Atalanta coach Stefano Colantuono certainly does not lack is the support of his club, despite a run of three straight defeats.
He this week received a firm vote of confidence, and responded by declaring he will still be in charge of the club in 10 years' time.
"It is unimaginable an Atalanta without Colantuono," said the club's president Antonio Percassi to the Eco di Bergamo newspaper.
"He has never been in doubt. The way we see football is that when we lose three games in a row, at least we can say we have Colantuono.
"He is the best coach possible for us to get out of a difficult moment and to save us."
Giuseppe De Luca could be the right man to help lift the Bergamese out of danger. The Italy striker, fresh from helping his side qualify for the European Under-21 Championships, should lead the Atalanta attack with German Denis.