Barcelona is not in any way in comparison with Napoli even though Napoli has shown some positive results in their last game and even at that in terms of statistics, Barcelona is still very much ahead of them and for sure be in the champion leagues, Barcelona will give many clubs a hard time and a run off for any of their winnings or even draw.
I am sure Barcelona may not lift the championship trophy this season but then there is the possibility of them placing themselves in a good position that can easily propel them to possible success.
We are talking about the actual Barcelona and the current Napoli performance without taking on consideration the winter transfer window and the injuries that might happen in the future.
So far Barcelona record are better than Napoli. In fact, Barca didn't lose any of their games against Napoli for at least four years if not more. I expect them to win but I wouldn't judge about which team is favourite until few days before the game in order to have a better look on the situation.
To be honest, this is the only match in the Uefa Champions League which will be a 50/50 in my eyes. None of them are doing great right now, both struggling in their own league. Napoli just lost to Roma 2-0 Yesterday and Barcelona had a tough victory against Almeria in their last La Liga match. Almeria is the team which is sitting at the bottom of the La Liga. Lewandowski seems out of touch and they have problems in both forward side and the defender side.
Napoli doesn't seem to be doing much lately. After that defeat against Roma, they are in the 7th spot. Whoever wins their match between Barcelona vs Napoli, will get eliminated in the Quarter Finals. I don’t see any of these 2 teams going to the Semi-Final. Napoli and Barcelona have a chance of doing something in January with transfer windows but Barcelona is struggling financially as well.