Miralem Pjanic scored a free kick in first-half stoppage time to give Serie A leaders Roma a 1-0 advantage over their nearest rivals Napoli after 45 minutes of action at the Stadio Olimpico.
The visitors are just two points behind Roma, who have a perfect record in their seven games so far this season, at the top of the table, and had previously had the best chances to open the scoring.
Goran Pandev saw his 37th-minute shot cleared off the line, with Daniele De Rossi making up the ground to clear a ball that goalkeeper Morgan De Sanctis had initially only parried towards the net.
The former Napoli stopper, playing against his old club for the first time since leaving them for Roma this summer, was fortunate again in the final stages of the half when he was saved by the woodwork.
Marek Hamsik picked out the clever run of Lorenzo Insigne, but the Italian forward hit a side-footed shot against the post, with the goal seemingly at his mercy.
In the fourth additional minute of the period, Roma were awarded a set piece which Pjanic dispatched into the top corner with a strike that curled away from Pepe Reina in the visiting goal.
Roma had previously threatened through De Rossi and Gervinho, but their attacking play was hampered by a injury to Francesco Totti, who left the field to be replaced by Marco Borriello on 35 minutes.
