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Even with those problems, they managed to draw with Barcelona. I don't think Barcelona have any serious problems that prevent them from winning, at least they are playing better than Napoli. Napoli are awful this season, as their play shows, I'll be surprised if they go any further
Both teams are equally bad in terms of consistency, but Barcelona is certainly better than Napoli. As bad as Barcelona's performance is, they are still a team that has the possibility of qualifying for the Champions League next season. Currently Barcelona is in 3rd place in the La Liga standings and they also have the potential to take second place from Girona if Girona loses points in the next match.
Napoli are not very reliable in the Champions League and basically they are more likely to fail to qualify for the quarter-finals. I think Barcelona will qualify for the quarter-finals, they have a good performance to be underestimated.
Yes, Napoli have total problems on all fronts this season, if I may say so. Overall a miracle can happen, but I don't believe in it and moreover Barcelona obviously look better. Yes, both teams have played badly, Barcelona on top of that are unstable in their league, but they should have enough of their skills to go further ahead