The Naples outfit's main challenge will come from reigning champions Juventus, who have won back-to-back league crowns.
"Juventus are a strong team and have made waves in the transfer market but there are other teams who can compete for the title and every year is different," he said," Benitez told reporters. "We will try to be competitive in all competitions - we have the Champions League to compete in and we are strong and equipped.
"In Serie A, there are other teams [who can challenge] such as Inter, Roma, Fiorentina and AC Milan. But we will fight until the end.
"There has been a very positive reaction from fans regarding my arrival and I am very happy with this. My desire is to work hard, give 100% to the club and to make the fans happy."
Napoli look likely to lose star striker Edinson Cavani to Paris Saint-Germain.