Carlo Ancelotti's Napoli settled for a point in a goalless draw amid high security at AC Milan on Saturday as evergreen Sampdoria forward Fabio Quagliarella equalled a Serie A record by scoring in 11 consecutive games.
Napoli defender Kalidou Koulibaly returned from the two-match ban he received at the San Siro a month ago after being targeted by racist chanting by Inter Milan fans.
Anti-riot police took up positions around the San Siro as part of stringent security measures Saturday, and the match took place without incident apart from some anti-Neapolitan songs before the game.
Napoli's Lorenzo Insigne also returned from suspension and formed a four-man attacking line-up along with Dries Mertens, Arkadiusz Milik and Jose Callejon.
"It was a totally different atmosphere and this is what we want to see in the stands. I applaud all the fans," said Ancelotti.
On the pitch most of the action occurred in the final half an hour.
Napoli finished with ten men after Fabian Ruiz received a second yellow card in injury time for a disputed handball, with Ancelotti banished from the sidelines for swearing.
Both goalkeepers pulled off saves with Gianluigi Donnarumma denying Napoli's Callejon after six minutes, and David Ospina saving a point-blank Mateo Musacchio volley.
Second-placed Napoli stay eight points behind champions Juventus who travel to Lazio on Sunday, while Milan, in fourth, missed a chance to close the gap on city rivals Inter, and could be overtaken by Roma who play Atalanta.
Quagliarella keeps scoring
Earlier, Sampdoria forward Quagliarella bagged a brace to equal Gabriel Batistuta's record of scoring in 11 consecutive Serie A games, in a 4-0 win over Udinese.
Quagliarella, who turns 36 next week, matched the mark after converting a penalty after 31 minutes, and added a second, again from the spot, on 56 minutes.
The evergreen forward also had a role in the other two goals -- in the build-up to Karol Linetty's third on 68 minutes, and the decisive cross for Manolo Gabbiadini to tap in ten minutes later.
"I'm speechless, just naming Batistuta gives me goosebumps," said Quagliarella.
"I kept thinking with every game that the run would surely be interrupted, but it kept going.
"I don't go out there to score goals, as I am just as happy if I provide an assist for a teammate."
Batistuta scored at least one goal per game in the opening 11 games of the season in 1994-1995 for Fiorentina. The Argentine went on to finish the season as the top scorer with 26 goals.
Quagliarella has had one of the best seasons of his career with Sampdoria.
He has scored 14 goals in his 11-match run for a total of 16 this season, to go top of the Serie A scorers ahead of Juventus star Cristiano Ronaldo (14).
The 25-times capped Italian international scored a career best 19 goals last season.
Sampdoria moved up to sixth, the final Europa League berth, and just two points off the Champions League places.
Sassuolo shrugged off the shock departure of Kevin-Prince Boateng to Barcelona by ending their four-month home win drought with a 3-0 success over Cagliari, keeping their Europa League push alive.