It seems like that napoli has been losing twotimes on the friendly matches which were not good at all. The fact that if napoli may even lose some key players and i think that's gonna be a very problem for napoli. Will inter beat napoli easily?
If Napoli lose the match against Inter Milan, of course they will lose points and make the clubs below them like Juventus and Acmilan able to reduce the points gap in the standings this season, maybe it's a friendly match that is not too serious for them to face but with a losing score like that as if it looks like Napoli is easy to beat

Friendly matches are not a guarantee that they have really declined, it could be part of their plan by seeing Napoli lose in a friendly match to make their potential opponents underestimate Napoli because they are considered to have experienced a decline. Moreover, I don't think their match brought out all the abilities they had. One of the things that makes them less ambitious about winning matches is because maybe they are careful and don't want their players to get injured in that match.