Gonzalo Higuain broke through Inter Milan's vaunted defence within the first two minutes of Monday's contest, turning and shooting in the box to give Napoli an early lead.
A uncharacteristic mistake by defender Jeison Murillo allowed Jose Callejon to pounce on the ball and lay off a pass for Higuain, whom deposited his 11th goal of the campaign.
Inter hadn't conceded a goal in the four matches prior to this one. There goes that.