It is too early to make such comment in my opinion. Because there are 22 more games to be played for Napoli. Everything can change significantly in this time period. Mazzarri isn't a very successful manager considering his whole career so I wouldn't be so sure about him already. He doesn't have a much different career than Rudi Garcia in the end.
This win over Cagliari was good for Napoli. This would surely improve their morale to play better in next games. But we need to see some consistency from them in the future to be able to trust them more for betting on them as well. For now I will continue to avoid betting on them.
That's right, we haven't been able to see Napoli in just a few matches and we have to look broadly, perhaps until the end of this season, regardless of Mazzarri's past or track record in the past playing the teams he coaches, but with Napoli it will certainly be different and also the management Napoli does not need to rush because nothing is instant in football, let alone building a team like Naoli, which has lost character after being abandoned by its coach at the end of last season.This win over Cagliari was good for Napoli. This would surely improve their morale to play better in next games. But we need to see some consistency from them in the future to be able to trust them more for betting on them as well. For now I will continue to avoid betting on them.
However, football is unpredictable, even though Inter is leading the group. Napoli are down but still in contention. If they focus on each game, progress gradually, and maybe change tactics, who knows? They may yet be influential this season. I hope to see a great recovery.