Napoli started well by winning all four matches in the league, but to be honest, I don't expect anything less from them. Aside from Florentina, the rest opponents they went up against were mid or bottom table clubs and I expected a win. Their real strength will be tested in their upcoming matches. If they can be able to win strong opponents like AC Milan and the likes, then I'm sure they'll do well this season.
Napoli have not tasted defeat in the league yet, although they have not yet faced a threat to them. However, I do not think they need to test their strength after winning the title last season. Napoli are still a very strong team, but we will see how strong they are this season in the next matches. In the next match they will face a strong team AC Milan, but it will be at AC Milan's home ground. In this match we will be able to test Napoli's strength
The Italian Series A has this uniqueness of small team beating small teams when least expected and going by that, if Napoli have not tested defeat this season, then we should give them some credit.
AC Milan is a big opponent for them but I think Napoli may collect the three points in that match, although this will not come easy. Safe bet for me is Napoli win or draw or under 3.5 goals.