Yes your points are valid but it is not good to underestimate a club like Atalanta because if you do, you may be surprised at what you will see tomorrow. No doubts Napoli have a very good record against Atalanta, winning them back to back last season and already defeated them in their first meeting of this season. It is more convenient to assume that they will also collect this three points especially as they are now playing at home. Napoli actually need this winning so they have to fight real hard to get it so as to keep their hope of Europa next season alive.
Yeah indeed we cannot underestimate one team but we also have to understand that they have a reason for that, Atalanta played badly lately so that they thought Atalanta would lose more points, especially when fighting a strong team.like Napoli and they play away.