Its the San Paolo, a draw is fine.
Napoli are flying high and believing they will win the league. We are the talks of a "crisis" every other game in the media. If we go to San Paolo now and they cannot beat us under this atmosphere, then its a blow for them. It will open the door for "its inevitable that Juve will win" talk. Of course if we win then this will happen even more, but a draw is enough to set the stage for the comeback.
Also, a draw will likely send Inter 1st (they play Chievo in San Siro). Inter won't be winning this scudetto so Napoli losing the 1st spot is positive.