Goals by Lorenzo Insigne and Gonazalo Higuain saw Napoli to a precious 2-1 win over Juventus on Saturday and compounded the champions` poor start to the season days before a crucial Champions League fixture with Sevilla.
Juventus had earned their only points from a win and two draws in their five opening games before travelling to a Napoli side that had hit 10 goals in their past three outings, including a 5-0 Europa League win over Club Brugge.
Bianconeri coach Massimiliano Allegri gambled by leaving Spanish striker Alvaro Morata on the bench and with Mario Mandzukic sidelined through injury it meant starts for Simone Zaza and Paulo Dybala.
Napoli, looking for just their second league win under new coach Maurizio Sarri, deployed their new-look 4-3-3 with Insigne, Higuain and Jose Callejon spearheading an attack that kept the visitors on their toes throughout a pulsating encounter at the San Paolo stadium.
While Zaza showed promise in the early exchanges, the Italy striker was all too often ruled offside after seeing a great chance pushed to safety by Pepe Reina.
Insigne broke the deadlock in style in the 26th minute to send the stadium into raptures.
Pouncing on a Mario Lemina error outside the area, Insigne found Higuain with a pinpoint pass which the Argentinian fired back into the Italian`s path and he beat Gianluigi Buffon with a low shot from outside the area.
Napoli could have doubled their lead on the stroke of half-time after Marek Hamsik found Faouzi Ghoulam with a defence-splitting pass but Buffon did well to parry the Algerian`s drive across goal as Higuain drove in at the back post.From the highs of reaching last season`s Champions League final having already sealed a first league and Cup double in 20 years, Juventus have come back to earth with a bump in recent weeks.
Despite an improved second half, the champions struggled, and mistakes proved costly too.
Higuain, who hit a brace in a 5-0 rout of Lazio last week, doubled Napoli`s lead on the hour after Hernanes gave up possession for Juve, the Argentinian powering past Simone Padoin to beat Buffon down low.
Juventus refused to buckle and barely a minute later the visitors reduced arrears when Lemina latched on to Dybala`s cross from the left to squeeze the ball past Reina from a tight angle.
Morata replaced Dybala with 20 minutes to play and soon after fired just a metre wide of Reina`s far post after collecting Roberto Pereyra`s ball on the edge of the area.
Juve pressed for a late equaliser, but were instead handed a third defeat of the season that leaves them 10 points behind leaders Inter Milan ahead of their home clash with Fiorentina on Sunday.Earlier, Roma warmed up for their Champions League clash at BATE Borisov with a comprehensive 5-1 win over promoted Carpi to move to within four points of Inter.
Rudi Garcia`s Serie A title challengers began their Group E campaign with a hard-fought 1-1 home draw with defending champions Barcelona a fortnight ago.
Days before their trip to Belarus, no less than five different Roma players hit the net in a one-sided performance that also saw goalkeeper Morgan De Sanctis achieve the rare feat of saving a penalty for the hosts.
Garcia, however, could be made to sweat on the fitness of Francesco Totti, Seydou Keita and Edin Dzeko after all three were forced off with suspected knocks.
"Having three players come off within 55 minutes means it was a costly victory," said Garcia.