Napoli dropped points for the second time this season in Serie A with a 1-1 draw at home to Hellas Verona on Sunday, but provisionally moved one point clear on top of the table.
Luciano Spalletti's side continued their unbeaten league run to rise to 32 points, one point ahead of AC Milan ahead of their Milan Derby clash with Inter Milan later on Sunday.
It was another impressive result against illustrious opposition for the visitors, and Giovanni Simeone continued his remarkable form in front of goal by stabbing in the opener after 13 minutes.
The Argentine striker has scored nine goals in his last seven league games, after finding the net six times during recent shock wins over Lazio and Juventus.
Napoli took five minutes to find the equaliser, Giovanni Di Lorenzo drilling in a low shot, while Victor Osimhen and Lorenzo Insigne were both denied by the post for Spalletti's side.
Verona finished the game with nine men after substitutes Daniel Bessa and Nikola Kalinic were both shown second yellow cards in the dying minutes, but they held on for a point that leaves them 10th with 16 points.
In Rome, Lazio eased to a 3-0 win over second-bottom Salernitana to leapfrog their city rivals AS Roma into fifth place.
Goals from Ciro Immobile and Pedro Rodriguez gave Maurizio Sarri's side a comfortable lead at the break, and Luis Alberto added a third after the visitors were twice denied by the woodwork.
Earlier, Udinese ended an eight-match winless run by coming from behind to beat Sassuolo 3-2, a result that lifted them to 14th, level on 14 points with their defeated opponents above them.
Sampdoria's crisis continued with a 2-1 defeat at home by ninth-placed Bologna, leaving Roberto D'Aversa's side 18th after a third consecutive loss.