Behrami admits their season will hinge on the result.
"The crowd will give us a hand, that is for sure," Behrami told the official Napoli radio station.
"Walter Mazzarri has been great at being able to read the various moments we're going through. Right now he is trying to take the tension off us, as he knows this type of match provides its own motivation.
"There are six points between us, so this game will be the tipping point where we understand who we are and what we can do. It will give a verdict and I'm sure on Friday night we'll know if we have to look ahead or over our shoulders.
"It is also important we don't get too unrealistic, as second place is something important that is worth defending. We proved that we can target bigger objectives, but it depends on us."