Forward Ademola Lookman scored twice inside the first half to help Atalanta to an emphatic 3-0 win at Serie A leaders Napoli on Sunday as the visitors moved second in the standings.

Lookman opened the scoring after 10 minutes with a volley from close range, netting a headed cross from Charles De Ketelaere.

He doubled the lead after the half-hour mark with a long-range strike from another De Ketelaere pass, before substitute Mateo Retegui added the third in stoppage time.

Atalanta, provisionally second on 22 points, have cut the gap to their opponents at the top to three points. They are one point above third-placed Inter Milan, with a game in hand, and Juventus in fourth.

"I think the team played well," Napoli manager Antonio Conte said after the defeat. "There were obviously areas, particularly around the goals we conceded, where we could have done better -- but I have nothing to criticise in terms of the will and commitment shown by my team.

"We have to take these results as lessons without being ashamed of what happened."