It was a humiliating defeat for Napoli. But I think in that match Napoli only fielded second-string players and there were several main players. It seems that Napoli is focused on improving their ranking in the League and playing well in the Champions League. However, losing by 4 goals like this is still quite embarrassing. Because if the reason is for the Champions League then the next match schedule is still very long away. Is this bad performance because Napoli don't really care about this match?
Yes, this can be said so because they lost without any reply to Napoli at home.
Almost most of the big Serie A teams when they play in the Coppa Italia they always lower these second layer players do not want to take excessive risks on players so that more are rested.
Even though the Champion League is still long with a time lag while Serie A still continues every week, Napoli may consider Serie A more important than the Coppa Italia.