Goals by winger Khvicha Kvaratskhelia and defender Amir Rrahmani steered Napoli to a 2-0 home win over Atalanta in Serie A on Saturday.
Kvaratskhelia, who was perfectly set up by striker Victor Osimhen, slalomed inside the box before giving Napoli the lead with a powerful strike into the roof of the net in the 60th minute.
Rrahmani doubled their lead in the 77th with a towering header following a corner.
Runaway leaders Napoli, who lost to Lazio last week, extended their lead at the top of the table to 18 points after second-placed Inter, on 50 points, fell to a shock 2-1 defeat to lowly Spezia on Friday.
Atalanta remain sixth on 42 points, seven above seventh-placed Juventus and Bologna in eighth - both with a game in hand - and Udinese in ninth.