Callejon swapped Real Madrid for the Serie A outfit in August and has made a bright start to life in Naples, scoring 15 goals in 38 appearances this season.
The Spaniard netted the only goal in their 1-0 win over Roma on Sunday, a result that takes the third-placed Napoli to within three points of Rudi Garcia's side.
And while runaway leaders Juventus are 17 points ahead of Napoli, Callejon feels that they are on the verge of something special.
Rafael Benitez's side play Fiorentina in May's Coppa Italia final and victory could set up the springboard for a title push in next year's Serie A, according to Callejon.
"This is a team that can achieve something next year," he told N+.
"We need another year, for other good players to arrive, and the goal within two years (is) to win something important, to win the Scudetto.
"This would be important for us.
"For us, the Coppa Italia is very important and we want to win that title, hoping that it is the first of many others."
The 27-year-old added that he was delighted in his decision to join Napoli, saying: "I left Real Madrid because I wanted to play more.
"And when Benitez called, he convinced me right away.
"I am very happy with my experience at Napoli and I would make the same choice again."
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