Napoli were held to a 0-0 draw by AC Milan at San Siro in a boost to Juventus' Serie A title defence.
The Rossoneri had only beat Napoli once in 15 league games prior to Saturday's encounter but came close to improving that record, with goalkeeper David Ospina making some crucial saves.
Carlo Ancelotti's side had won their previous two top-flight games since losing on this ground to Inter last month, but a relatively flat performance left them unable to worry Gianluigi Donnarumma's goal unduly and they lost Fabian Ruiz to a late red card.
Patrick Cutrone hit the side-netting in a bright opening spell from Milan, although neither side looked prepared to sit back and play for a point in a combative first 45 minutes.