Lorenzo Insigne had opened the scoring, but an Edin Dzeko brace, Cengiz Under and gift from Mario Rui saw Roma shock leaders Napoli 4-2.
This means the run of 10 consecutive Serie A victories is ended, but above all the gap at the top of the table is now one point and Juventus have a game in hand against Atalanta, as it could prove to be a pivotal weekend in the Scudetto race.
The Derby del Sole had the Serie A leaders forced to do without Marek Hamsik due to flu symptoms, missing his first Serie A start since April 2015, which was also against Roma. The Giallorossi were coming off back-to-back defeats to Shakhtar Donetsk and Milan, but are unbeaten at the San Paolo since a 2-0 result in November 2014.
Both sides had huge chances in the opening couple of minutes, as Mario Rui was caught in possession and Diego Perotti nodded over the bar. Moments later, Lorenzo Insigne controlled a Jorginho long ball, but his shot was too weak to surprise Alisson.
Insigne scored at the second attempt, sticking out a foot to turn in the Mario Rui drag-back from eight yards to give Napoli the lead.
Barely a minute had passed when Roma equalised, as Cengiz Under saw his attempt take a deflection off Mario Rui to loop over a helpless Pepe Reina into the far top corner.
It was non-stop at the Stadio San Paolo, Dries Mertens curling wide, then Alisson beating away a low Insigne volley on Jose Callejon’s cut-back and Kostas Manolas flinging himself in the way of Piotr Zielinski’s follow-up.
Insigne’s trademark right-foot curler was just off target, but Roma turned the game around completely with Edin Dzeko’s header looping into the far top corner, out-jumping Raul Albiol on an Alessandro Florenzi cross.
A Mertens angled drive was deflected inches wide off Manolas, while both sides continued to go at it in an action-packed game.
Napoli laid siege to the Roma goal after the restart, as Alisson palmed away an Insigne volley at the near post and Jose Callejon hit the frame of the goal directly from the corner flag.
Insigne flicked on the ball, swerved past another tackle and his curler from the edge of the box flashed inches wide of the far post.
Just as Napoli were pouring everything forward, Dzeko scored a stunner to increase Roma’s lead. He cut inside from the right and curled a spectacular left-foot finish into the far bottom corner from the edge of the box.
Arkadiusz Milik made his comeback for the first appearance since rupturing his ACL in September, but Insigne continued his personal battle with Alisson, forcing a double save from close range at the near post.
Yet Mario Rui absolutely gifted Roma with a fourth goal, his ludicrous back-heel flick clearance inside his own six-yard box giving Diego Perotti a clear shot from eight yards.
Lorenzo Pellegrini came off the bench and his first touch was a horrible back-pass that Alisson had to tip over the bar. This led to an indirect free kick from six yards that Florenzi cleared off the line from Mertens.
In stoppages, Mertens got one back with a daisy-cutter into the near bottom corner from the edge of the area. It was scant consolation, but the crowd cheered and applauded their team at the final whistle.
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