Napoli forward Lorenzo Insigne scored his seventh goal of the campaign in a 2-0 victory over Sassuolo at the San Paolo.
Carlo Ancelotti's men had suffered their second defeat of the season last week when fell to a 3-1 loss at Juventus and, with the Bianconeri having maintained their 100 percent record on Saturday, needed the victory to close the gap from the leaders back down to six points.
And they got the perfect start when Adam Ounas rifled in his first of the season to after just three minutes.
Despite dominating the contest, Napoli had to wait until the 72nd minute to make the points safe when Insigne curled an effort into the top corner from the edge of the box.
Sassuolo saw Rogerio sent off on 87 minutes for a knee-high tackle on Jose Callejon.