Second-place Roma travel to Naples knowing defeat could see defending champions Juventus extend their 11-point cushion at the top of the standings.
Roma have a game in hand and are six points clear of Napoli, who are third and hold the last Champions League qualifying spot.
"I cannot lie, the scudetto is out of our reach," Napoli coach Rafael Benitez said. "But we can still point to finish second.
"I have no doubt in my mind that we can end the season in second place.
"But in order to achieve that, it's crucial we beat Roma on Sunday."
Napoli will have to show a vast improvement if they are to upset a Roma side unbeaten in seven games and with the best defensive record in the competition.
Benitez's side have drawn their last two league games, including Sunday's 1-1 result at Livorno.
"We are disappointed to have given away points in our last two games," Napoli midfielder Marek Hamsik said."We must learn from our mistakes in order not to repeat them in the future."
The good news for Napoli and Benitez is that the team's top scorer Gonzalo Higuain will be available to play having missed the game at Livorno through suspension.
Rivals Roma are also looking to return to winning ways having been held to a goalless draw at Inter Milan.
"We have only lost two league games this season," Roma coach Rudi Garcia said. "We want to win all our remaining games.
"We are capable of taking three points anywhere and we have proved that already.
"On Sunday we have an important game and I'm hopeful I will have most of my players available."
Defenders Dodo and Douglas Maicon as well as midfielders Miralem Pjanic and Francesco Totti have recovered from their respective injuries and will be available for selection.
Roma will be without midfielder Daniele De Rossi, who will serve his first game of a three-match ban this weekend.