The former Italy and Napoli coach is well aware that Group A, consisting of Napoli, Man City, Bayern Munich and Villarreal, is one of the toughest in the competition but says the Naples outfit need to have faith if they are to succeed.
"Undoubtedly, it is the most difficult group of all but Napoli must have faith in their chances. The club have reinforced well in the transfer window and are growing," he told TuttoMercatoWeb ahead of Wednesday night's meeting between the two clubs at Etihad Stadium.
"Their inexperience at this level can be countered with the right amounts of enthusiasm and ruthlessness.
"City's attackers are very strong but Napoli's strike-force is equal to them.
"It will be a difficult game but not impossible even if City are one of the most feared clubs in Europe at this moment."