Barcelona wasn't in their good form, but it's a big joke if they're lose against Shakhtar Donetsk and Royal Antwerp because both of them are in different level. If Manchester United was in this group, I believe Manchester United will able to qualify for knockout stage.
Either Barcelona or Napoli win the match, their next match is against Arsenal which I think they would lose.
In the UCL the first round will be in Napoli, so losing it is probably realistic. But the best thing is at least they don't lose by more than 1 goal. I also still feel confident that Barcelona could have drawn in the first round. So they have points for the 2nd game at Camp Nou. Besides, the game is still February. There is still a transfer break that can be taken advantage of. For Napoli and Barcelona I guess Barcelona will win and continue the round of 8 big teams.