Second-placed Roma are now 11 points behind Juventus who entertain Empoli later on Saturday.
The home team scored in the 25th minute when Alessandro Florenzi set up Pjanic after a string of precise passes and his low shot beat keeper Mariano Andujar.
Pjanic, who was also on target when Roma last won at home against Inter Milan in November, gestured towards the press box after his goal.
"Was my celebration controversial? Some people in the press talk too much," he told Sky Sports Italia.
Napoli seem to bring out the best in Bosnian playmaker Pjanic who netted twice in last season's 2-0 home win over Rafa Benitez's men.
Rudy Garcia's Roma controlled the opening half and pressed their opponents all over the pitch, leaving few openings for the quick visiting forwards.
The second half was a different story as Napoli attacked furiously without managing to break through.
Belgian winger Dries Mertens was a constant threat and brought out the best in Roma keeper Morgan De Sanctis.
Napoli had their best chance when a Jonathan De Guzman
pass was volleyed by Manolo Gabbiadini only for De Sanctis to come up with a spectacular one-handed save.
Benitez's team, who have lost four straight games away from home, are fifth in the table.
(Editing by Tony Jimenez)
Share
