If we look at their performance this season, both in the Champions League and the domestic league, both teams have experienced a setback in their game. Both Barcelona and Napoli are of course the two best teams in the previous season and even this season they have quite quality players in their team so this meeting is really difficult to predict the final result of the two legs they will play. However, apart from that, both teams have experienced setbacks in their front lines where their two attackers have not been able to provide their best quality this season, so it is very likely that the next match will result in a draw.
Yes, of course there is still time for both teams to improve the quality of their game because there is still plenty of time for them to improve in terms of their game. Xavi of course doesn't want them to fail again this season because it would be quite disappointing if they had to go out in the round of 16. Barcelona success in the Champions League declined drastically after Lionel Messi was no longer with them, where Barcelona had difficulty making it to the final. We'll see this season whether Barcelona can progress further under Xavi's guidance or will they be knocked out by Napoli.
Statistically, Barcelona still has a better record in domestic competitions than Napoli, and if we judge in terms of squad depth, Barcelona is still superior, Xavi has a more balanced squad depth when compared to Mazzarri. In fact, there are many differences, but in terms of the current consistency of the two, They have recorded unsatisfactory results.
I think either Xavi or Mazzarri will make changes to their squad in an attempt to go further in the UCL this season. however, personally I predict that Barcelona with all its attributes will advance to the quarter finals, which does not mean underestimating the strength that Napoli has.
On other hand, reaching the UCL final this season is quite difficult for Barcelona, because there are still teams that are more consistent than them. as we know, Madrid, Man City and Bayern Munchen are the clubs that are the favorites to win the UCL this season. Barcelona will need a lot of luck to get to the final, But I don't think they will be knocked out by Napoli in the last 16.