The central Italian side have scored nine goals on their way to three wins from as many starts in their Serie A campaign.
Benitez has noticed a worrying trend with his side's defence and is hoping that the rearguard can put in a strong performance just in case his attack doesn't fire.
"Our team usually makes a real performance in the offensive phase, whereas we sometimes leave some empty spaces in the defensive department," Benitez said.
"I'm satisfied if we continue scoring two or three goals in every match, as we have done so far.
"If we manage not to concede any goal, it will be even better.
"It's important to score goals and we'll work on improving in the defensive phase."
Milan lost to Verona on the opening day of the season but warmed up for this weekend with a comfortable win over Celtic in the Champions League and Benitez understands it is going to be a tough contest.
"We'll be facing a very difficult match against a great team, such as AC Milan," he said.
"It doesn't matter whether we are the favourite team, or they are the favourite team; what is important is what we can make on the pitch."
Milan head coach Massimiliano Allegri was also complementary of his foe, praising Benitez and several of Napoli's star attacking players.
"In such a short time, Benitez has done a very good job because it was difficult to change so many players and change the formation from three defenders into 4-4-2 or 4-2-3-1," Allegri said.
"Therefore tomorrow's match is going to be difficult for both teams and I believe it's going to be a balanced match.
"They have excellent forward players like (Gonzalo) Higuain, who is a special player because he seems to be absent from the match, whereas he is always focused on the match.
"(Marek) Hamsik is improving year after year and is becoming one of the best players at European level."
Allegri is hoping that his own star forward Mario Balotelli can have an impact on the match, stating that while he has been impressed with striker's attitude, he is still adjusting to life at the Rossoneri.
"Balotelli played the last match with (strike partner Alessandro) Matri and he played a bit more on the left in order to use his best skills to dribble and shoot - he has made many sacrifices," Allegri said.
"He has to improve, but I repeat once again that this is the first year that he plays as a protagonist and regular player, therefore he has to improve not only under the technical and tactical point of view, but also under the mental point of view."
