Club president Aurelio De Laurentiis announced on Wednesday that the 25-year-old forward has already passed a medical, and the Partenopei are expected to complete a deal imminently.
Benitez is thrilled to have Higuain, whose older brother Federico plays for the Columbus Crew, at Stadio San Paolo ahead of the coming campaign and has backed him to slot into the side seamlessly following the departure of Edinson Cavani.
"We needed a player like Higuain. We were looking for a quality player, for someone playing at the highest level," Benitez told Corriere dello Sport. "We have signed a player who comes from Real Madrid and who has scored a hatful of goals. He will adapt very well to our system - an attacking system.
"We are all working together to ensure the players we want arrive. We have to sign players who will do well for Napoli for the next three or four years."
Napoli has already signed Jose Callejon, Raul Albiol, Dries Mertens and Rafael, while it is also on the verge of securing the services of Pepe Reina on loan, and Benitez believes the club has taken a giant step forward following the summer spending.
"Players who come from clubs like Real Madrid, PSV and Liverpool can only do us good. We had a great squad already, but we can move forward," Benitez said. "For Napoli, these signings represent a quantum leap."