Rafael Benitez's side paid roughly €40 million to sign the 25-year-old Argentina striker and Campagnaro, who ended his four-year stint at the Stadio San Paolo to join Inter this summer, is certain his compatriot will be a success.
"Napoli have signed a champion," the 33-year-old told reporters. "He is a player who has done well at whichever club he has been at and I've spoken to him about the enthusiasm of the fans in the city.
"He will do very well there, Napoli are a great club and the city is a special place."
Both players featured in Argentina's 2-1 victory in a friendly against Italy at the Stadio Olimpico on Wednesday, with Higuain opening the scoring in the 21st minute.