The two clubs form part of a chasing pack of five separated by just four points, although Roma's position in sixth is perhaps a little false given a run of six wins from seven games before Christmas.
Napoli, conversely, lost two games from their last three and suffered a two-point deduction for their role in the match-fixing scandal, but boss Walter Mazzarri remains optimistic.
He told the Corriere dello Sport: "We have eight more points than we had this time last year.
"We've made a few mistakes in some matches but on the whole the team played very well in the first half of the season.
"I saw a good reaction from the players in our last game of the year (a 2-0 win at Siena) when it wasn't easy to lift ourselves following two defeats.
"Now we're just thinking about the match and rounding off the first half of the season in style.
"Roma are a very good team and it will be a very difficult game, but one that should fascinate both sets of fans. They have made good signings and Zdenek Zeman always gets his teams playing world-class attacking football.
"We will need to be at our best to get something from them."
Zeman reassured Roma fans that his players were not suffering from jet-lag on their return from a winter trip to Florida, also stressing his determination to hold on to star names like Pablo Osvaldo and Mattia Destro.
The veteran Czech said: "I think this is a good squad and it's to be expected that some names will be bandied about until January 31. Some stories are true but others are false.
"I'm glad my players are wanted by other clubs as it means they are doing well. Meanwhile, I've asked for Cristiano Ronaldo and Lionel Messi.
"It's good to have an enthusiastic group of players. It's better than them being depressed, after all. But the table says we should have done more and we will try to improve.
"We are a good side but we will have to prove it in the second half of the season."
Banned defenders Paolo Cannavaro and Gianluca Grava aside, Napoli have a clean bill of health but Roma are without suspended defender Marquinhos and injured midfielder Rodrigo Taddei.
The Giallorossi have had the edge in this fixture over recent years, having claimed 10 points from the last 15 available to them at the San Paolo.