The Partenopei go into the game at San Siro with a 100 per cent record in Serie A this season, having overcome Bologna, Chievo and Atalanta to move five points clear of Milan already.
Allegri has warned of the danger posed by the attacking players at Rafa Benitez's disposal, but insists the overall gap in quality between the sides in negligible.
"They [Napoli] have excellent forward players," 46-year-old told a press conference.
"[Gonzalo] Higuain is devilish. Even when seems like he's absent in the game, he is always there. [Marek] Hamsik is proving to be among the best in Europe, [Jose] Callejon is a high-quality international.
"It will be a good game. If Napoli are favourites, it's only because they have nine points from three games and we have four. But we can recover lost points.
"It will be a very balanced game. They give away very little space and depth and we have to be good at not giving anything away too. We need to overcome their counterattacks. I believe in my boys. We are aiming for the top three."
Allegri, who saw his side overcome Celtic 2-0 in their opening Champions League group game on Wednesday, also spoke positively of Benitez and the changes he has brought to Stadio San Paolo since arriving in May.
"Napoli are playing very good football at the moment," he added.
"In such a short time, Benitez has done a very good job because it was difficult to change so many players and change the formation from three defenders into 4-4-2 or 4-2-3-1.
"Napoli will be a tough game for us, but it will be tough for them too."