Napoli is in great form right now, it's true. And stopping Napoli is very difficult now. The performance of Napoli players in every match is exceptional. There is no doubt that Napoli is their favorite opponent of Frankfurt. Napoli is also in better form than Frankfurt. But don't forget this is the Champions League platform. There is no opportunity to neglect any team here. Frankfurt is not favourites, but they have a chance to win. Last season we saw a mighty Bayern Munich team knocked out of the Champions League after losing against Villarreal. And so if Napoli makes any mistake on the field they are likely to lose.
It will not happen easily. Frankfurt needs to work even harder than all of the teams in serie a to stop napoli. Napoli was an unbeaten team since it was losing against intermilan. Frankfurt is facing a very difficult situation once it must have dealt with the best team in italy. I think that it doesn't matter a lot whether this is champion league or not. this is another match that is easy to predict as the match between brugge against benfica. People know that if napoli has very big chance to win against frankfurt.
So many napoli's players are on fire now. I would not be surprised if napoli can win with huge scores. Frankfurt will be lucky enough if it can win against napoli.
The whole point about Napoli is the situation of the players they currently have in their team because most of the players are on their good days and they are definitely going to receive good offers from big teams soon. That's why I think even if Napoli finishes the Champions League in a good situation they will still have to make plans forth next season otherwise they are going to lose many players, however, they have strong competitors in the champions league where they will regret if they make a single mistake.