Juve are leading Italy's top division by four points over second-placed rivals Napoli, ahead of the league fixture between the two at the Allianz Stadium, with five games remaining.
Many have called it the "title decider" but for Allegri, his side still have difficult hurdles against Inter, Roma and a Coppa Italia final against AC Milan to negotiate.
He told the club's website: "Now we are heading into a mini-league in which we have a four-point lead with five matches remaining. Juventus v Napoli is important and will be a great game, but not decisive.
"We must be ready not only for tomorrow's match, but for this final stage of the season in which we will also face Inter and Roma, as well as Milan in the cup final."
Turning his attention to Sunday's opposition, Allegri was full of praise: "Napoli have been going for the title since the start and we know this is a crucial match for them. They're enjoying an extraordinary season, as they have in recent campaigns.
"Maurizio Sarri has done a fantastic job there. He has technically gifted players and he has created a team that plays a great brand of football. They have become a major force in Italy and Europe."