Kolo Muani scored on his debut, but Matteo Politano snatched an overdue equaliser and Romelu Lukaku slotted home what transpired to be the winner for the table-topping hosts.
Napoli head coach Conte, who won the Serie A five times as a player and three times as manager, ended Juve’s unbeaten league run with the slender success on Saturday.
Motta’s first full season at Juventus has seen the club become the league’s draw specialists, with 13 stalemates and eight victories before their showdown with Napoli inside the Stadio Diego Armando Maradona.
This campaign appears to be a learning curve for Juve under Motta, whose tactical methods appear to be beyond some players. There is hope that next season their goal will be to thrive, in terms of both results and eye-catching performances.
The Juventus boardroom are fully aware that patience can be a precious commodity in sport, and are backing Motta with January transfer signings that include the arrival of Paris Saint-Germain striker Muani on loan.
Motta has shown little faith in forward Dusan Vlahovic since December, which has paved the way for a clutch of English Premier League sides to show interest in the Serbia international.
After Muani broke the deadlock on the cusp of half-time, volleying home from eight yards, the Bianconeri were forced to defend throughout a one-sided second-half.
Goalkeeper Michele Di Gregorio made a spectacular save to clear Lukaku’s header off the line after the turnaround, but was unable to prevent André-Frank Zambo Anguissa nodding home Matteo Politano’s pinpoint cross on 57 minutes.
Livewire Politano, whose attempt skimmed off the crossbar in the first half, came close to snatching the lead only for Andrea Cambiaso to deflect his volley over the goalmouth.
When Manuel Locatelli’s sliding tackle clumsily sent Scott McTominay tumbling in the area, the referee was forced to award a spotkick.
Belgium ace Lukaku cleverly rolled his penalty down the middle after Di Gregorio dived out of the way, which sent ruptures around the jam-packed stadium. Lukaku’s 200th career goal, all bagged in Europe’s top five leagues, was a classy finish.
With the hosts dominant, out-of-favour Vlahovic was introduced with just nine minutes on the clock. However, he provided no threat just like his late arrival to tackle Club Brugge in the Champions League in midweek.
All of the goalmouth action was at the other end of the pitch, with Douglas Luiz almost scoring an own goal and Weston McKennie doing a superb job to brilliantly block Cyril Ngonge’s effort.
Juve may have only suffered one league defeat this season, but they now lie 16 points behind Conte’s Napoli after once again dropping points from leading situations. Motta’s side would be better off by a whopping 17 points if they had been more resolute.
After this underpar display it is very clear that Motta needs to bring in another defender during the January transfer window, and maybe he should sign someone to give new acquisition Muani better service.