As the Rossoblu prepare to play yet another game behind closed doors in southern Sardinia, Montella is anxious a lack of travelling support will hinder his own side's chances of securing the win.
Cagliari have beaten Torino and Sampdoria during their fans' ongoing exclusion from the new build, results which have more or less guaranteed the club's top-flight status despite their off-field difficulties.
Montella told La Repubblica: "Playing without supporters makes it a completely different match. You can perhaps lack that bit of adrenaline.
"Cagliari are getting used to it and, despite their unhappiness with the situation, it gives them a small advantage.
"I would have liked to play in front of fans and Fiorentina did request it."
La Viola could get the jump on third-placed AC Milan before the two Champions League rivals meet in Florence next weekend, but Montella has put that encounter to the back of his mind.
"I say this with absolute sincerity, I am not thinking about the Rossoneri right now," he added.
"It is vital for us to get points from the Cagliari game and any personnel choices will revolve around this match only.
"If someone decides not to put a tackle in to avoid getting a yellow card, they will be substituted."
Borja Valero is suspended for Fiorentina while striker Giuseppe Rossi has stepped up his recovery from a cruciate ligament injury.
Montella is searching for a viable replacement for his Spanish midfielder, adding: "There isn't another player with his characteristics in the team.
"Maybe if we decide to be more attacking we can use Mati Fernandez or even Romulo."
Cagliari boss Ivo Pulga is without suspended striker Nene as he plots an unlikely assault on the top half of the table over the season run-in.
"We are doing a lot better than we did in the first half of the season," he said. "But I am convinced that our actual performances should have got us into 10th place or better.
"We hope we can guarantee our survival as soon as possible so we can concentrate on getting the best possible results from our remaining games."