Serie A is bogged down in another refereeing controversy as Napoli and Juventus have become involved in a slanging match over their match yesterday.

Juventus, 3-1 winners, reacted angrily after Napoli president Aurelio Di Laurentiis said a hairline decision which allowed Juve's second goal to stand was "either bad faith or incompetence".

Juve's win took them three points clear of AS Roma at the top and 13 ahead of Napoli, who are joint fifth.

"We are tired. Juventus are a strong team, and if they are helped by the referees, they become unbeatable," Di Laurentiis said on Twitter.

"It's unacceptable that six referees cannot see two players offside. Either it is bad faith or incompetence. These six referees should be banned for a long time."

Napoli claimed that Martin Caceres was offside when he headed Juve's second goal, although replays showed it was only a question of millimetres, if at all.

They were also angry after having a goal of their own disallowed shortly afterwards for a foul by Kalidou Koulibaly on Juve goalkeeper Gianluigi Buffon.

"They taught me a phrase when facing Juventus: 'It can happen.' On the offside it is very difficult to tell as Maggio is right behind Caceres," Napoli coach Rafael Benitez said. "It can happen.

"The Koulibaly goal that was disallowed, it can happen. Koulibaly jumped, the goalkeeper fell into him, it was Buffon's momentum that took him towards the defender. It is not a foul."

Juventus, involved in a similar row following their 3-2 win over AS Roma in September, said they won fair and square.

"It was a transparent win, the result of a more than positive performance. I reject Di Laurentiis's accusation," said chief executive Giuseppe Marotta.

"The value of the team emerges during the course of the championship and in matches such as this one."