Barcelona will definitely beat Napoli, Walter Mazzari is not even the man for Napoli, this are just try and error coaches, for long term, you need a better and tactical genius for that club.
the situation might be different when Napoli's performance is like last season, with the same players and coach. but the situation is different, Xavi and the Barcelona squad will be more favored to win in advancing to the next round.
Barcelona will be the team that is more appreciated in this match. As the top team in the group, they will expect to meet a light opponent in the 1/8 round to facilitate their advance into this year's Champions League. However, Barcelona has been in decline this season. And when Robert Lewandowski was tormented by injuries and his age, Barcelona gradually became a mediocre team. Therefore, it is not certain that Barcelona will win this match because, after all, Napoli was the defending champion of SERIE A last season.