MILAN, Oct 15 (Reuters) - Edin Dzeko scored a goal either side of halftime to set up a 3-1 win for AS Roma away to Napoli in the battle for second place in Serie A on Saturday.
Mohamed Salah also played a key role, setting up the first goal and scoring the third himself, as Roma leapfrogged their opponents.
Kalidou Koulibaly, whose mistake led to the first goal, replied for Napoli who suffered their first home defeat in Serie A since Maurizio Sarri took over as coach at the start of last season.
Napoli and Roma have alternated in providing the biggest challenge to the recent dominance of Juventus with each finishing as runners-up to the Turin club twice in the last four seasons.
Roma have 16 points, two behind Juventus, who host Udinese later on Saturday.
Napoli, who sold leading scorer Gonzalo Higuain to Juventus in the close season and then lost his replacement Arkadiusz Milik to a serious knee injury last week, have 14 points after their second successive defeat without scoring.
Both sides created chances in an end-to-end first half but it was the visitors who went ahead two minutes before the break.
Salah won the ball off Koulibaly on the edge of the area and his cross was swept home by Dzeko from 12 metres.
The Bosnia forward took advantage of more poor defending when he rose unmarked at the far post to head in Alessandro Florenzi's free kick nine minutes after the re-start.
It was Dzeko's seventh Serie A goal of the season, only one short of his tally for the whole of last season.
Koulibaly kept the game alive when he headed in from a corner four minutes later and Napoli began to look capable of grabbing an equaliser.
Instead, Daniele de Rossi sent Salah clear of the Napoli defence and the Egyptian guided his shot wide of Pepe Reina to seal Roma's win. (Writing by Brian Homewood; Editing by Clare Fallon)