Rafael Benitez's side reportedly paid €37million to sign Higuain from Real Madrid in July, with the 25-year-old expected to replace prolific frontman Edinson Cavani after his move to Paris-Saint Germain.
And Campagnaro, who ended his four-year stint with the Stadio San Paolo outfit in order to join Inter during the same month, is certain his fellow Argentine will be a success.
"Napoli have signed a champion," he said.
"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."
Higuain and Campagnaro both started in Argentina's 2-1 friendly victory over Italy at the Stadio Olimpico on Wednesday.
Former River Plate striker Higuain opened the scoring in the 21st minute.
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