But I think that the term "unexpected" is also a question of timing when you declare a team an unexpected or expected winner. Before this season started, not many would have thought that Napoli at this point in time would be among the top favorites for the Champions League title. That is why Napoli would still be an unexpected to winner to me, looking at it from a pre season standpoint. And considering their whole season and performances (actually no luck, just skill), they would be a well deserved winner in the end if they are able to keep their level until the very end.
Napoli have been unpredictable this season, not only in the Champions League, even in Serie A, in my opinion, they have been unexpected by having a very large difference in points than the other teams. Napoli have great hopes of being able to talk more in the Champions League this season, moreover they also have a great chance to advance to the next round after they met AC Milan in the draw. And it's also very likely that if they can qualify they will meet another Serie A team.