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.
I wasn't surprised that Napoli lost to Roma in the Italian League because, once the two players were sent off, there was nothing more they could do. However, I wasn't expecting Napoli to lose to Roma, if the red card hadn't spoiled the game, I thought Napoli would score to win or draw the match. This season, the both team are not playing well, but Barcelona is worse than Napoli.
Well if you watch that match Roma also hard time keeping Napoli at bay as they also had 7 yellow cards so it's safe to say that Napoli still has that strong aggressive side to put opponents in pressure and so will they try also against Barcelona. Barcelona on the other hand have good attack but not a strong defense so I think Napoli will have easy time dealing with Barca's defense whenever their match happens. I expect both teams to score in tht match.