As Dries Mertens stood over the ball, Napoli fans knew there was only going to be one outcome.
The Belgian had already scored 19 Serie A goals for the Italians this season, and a stunning strike from distance on Sunday against Empoli made it 20.
With a short run-up, Mertens whipped the ball into the top corner with Lukasz Skorupski having no chance of getting in the way, such was the power of the shot.
The strike put the visiting side 2-0 up after 24 minutes following Lorenzo Insigne's goal just minutes earlier, though Mertens had already missed a penalty in the opening stages.
Napoli currently sit second in the Italian top flight, chasing title-holders Juventus who have again opened a large gap at the summit.