Scott McTominay scored the only goal as Napoli won at Torino to extend their lead at the top of Serie A to four points.
The Scotland midfielder struck on 31 minutes to give Napoli their second straight win since the international break.
The 27-year-old now has four goals from 12 games since joining Napoli from Manchester United in August.
It was McTominay’s second goal in three games having scored in Napoli’s 1-1 draw at title rivals Inter Milan before the international break.
“I’ve scored two important goals in the last three games, but the whole team deserves credit,” said McTominay.
“We’re improving and we’ve got to keep this up. The great results we’re getting is proof that we’re working well.”
Coach Antonio Conte, who took charge in June, added: “We quietly signed [McTominay] and the club and sporting director Giovanni Manna did a great job at understanding what he could bring to Napoli.
“But the same goes for every new recruit. We’re a team that’s on the up and the growth of a team happens through the steps each individual player must take every week.”
Scotland striker Che Adams missed a great chance to open the scoring for Torino as he sent a free header wide from close range.
Napoli went into the weekend a point clear with four teams level in second place, including Fiorentina and Inter Milan, whose game was abandoned after Edoardo Bove collapsed on the pitch.
Lazio lost 3-1 at Parma while Atalanta’s game at Roma is at 19:45 GMT on Monday.