(Updates with later matches)
* Dzeko scores brace in Roma win
* Roma leapfrog Napoli to go second
* Dybala scores twice as leaders Juventus win
* Campagnaro scores at both ends in Pescara draw
MILAN, Oct 15 (Reuters) - Edin Dzeko scored twice to set up a 3-1 win for AS Roma away to Napoli in the battle for second place in Serie A on Saturday and Paulo Dybala also notched up a brace for leaders Juventus in their 2-1 win over Udinese.
Pescara defender Hugo Campagnaro scored at both ends in the 1-1 draw with Sampdoria and his team also missed a penalty and had a player sent off before halftime.
With the season taking on a familiar look, Juventus increased their lead to five points with Roma in second and Napoli a further two behind after their first home league defeat 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. Juventus are chasing a sixth successive title.
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, fielded Manolo Gabbiandini in attack but he was substituted to jeers early in the second half.
Both sides created chances in an end-to-end first half but it was the visitors who went ahead two minutes before the break.
Mohamed Salah won the ball off Kalidou 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 restart.
It was Dzeko's seventh Serie A goal of the season, only one short of his tally for the whole of last season.
Koulibaly headed one back for Napoli from a corner four minutes later but, as they pressed for an equaliser, Daniele de Rossi sent Salah clear of the home defence and the Egyptian guided his shot wide of Pepe Reina for Roma's third.
Udinese took a shock lead after half an hour at Juventus when Jakub Janto intercepted a wayward pass and scored with a low shot which Gianluigi Buffon got a hand to but could not stop.
Dybala replied two minutes before halftime, curling an exquisite free kick over the wall and into the net, and then converted a penalty in the 52nd minute after a careless foul on Alex Sandro.
Campagnaro's eventful evening began when the veteran Argentine inadvertently turned Lucas Torreira's free kick into his own net after 12 minutes but he made amends by heading the equaliser from a corner nine minutes later.
Pescara had Andrea Coda sent off for a second bookable offence on the stroke of halftime then missed a penalty five minutes after the restart when Gianluca Caprari's shot was saved by Emiliano Viviano.
"We are a team that scores goals for us and the opposition, so in a way it's innovative," said Pescara coach Massimo Oddo. "In the circumstances, we couldn't have done much more than this." (Writing by Brian Homewood; Editing by Clare Fallon)