Napoli coach Maurizio Sarri rested Polish striker Arkaduisz Milik for the visit of high-flying Chievo and his replacement, Manolo Gabbiadini, repaid Sarri's faith by hitting a 24th minute opener from Jose Callejon's delivery.

Hamsik's impressive 39th minute strike, the Slovakian running on to Lorenzo Insigne's precision pass to beat Stefano Sorrentino at his far post, was his 100th in Napoli colours since joining the club from Brescia in 2007.

Napoli remain second, a point behind Juventus after the champions warmed up for their Champions League clash away to Dinamo Zagreb on Tuesday with a cagey 1-0 win at Palermo.

Chievo struggled to make an impact in the opening half, and despite a brief flurry in the second period the visitors -- sitting fifth just two points behind leaders Juventus ahead of Saturday's fixtures -- rarely threatened.

When Antonio Floro Flores replaced the ineffective Riccardo Meggiorini just after the hour, the Italian soon had a great chance to reduce the arrears.

But after beating the offside trap to go clear on Pepe Reina, Floro Flores lost his footing as the 'keeper rushed out and Kalidou Koulibaly came in to clear.

Milik had replaced Gabbiadini on 64 minutes but the Polish international, with four league goals this season, couldn't add to his tally.

Sorrentino did well to stop Milik at the second attempt after the towering striker latched on to Insigne's low pass, and the Pole's poor control let him down on a long ball from Hamsik on the stroke of full time.

Hamsik is now 15 short of equalling the all-time scorers' record at the club, held by former icon Diego Maradona.