Napoli’s hopes of catching Serie A leaders Juventus suffered a dent after drawing a blank at top-four rivals AC Milan.

Returning to the San Siro exactly one month after defender Kalidou Koulibaly was the subject of alleged racist chanting in a 1-0 defeat at Inter Milan, Napoli this time settled for a goalless draw.

Jose Callejon clipping the crossbar was the closest Napoli came to a breakthrough, although both goalkeepers were pressed into action on multiple occasions in a see-saw encounter.

Napoli closed the gap on Juventus to eight points, but the Turin giants could further their lead into double digits when they travel to Lazio on Sunday.

To compound the Partenopei’s disappointment, Fabian Ruiz was given his marching orders deep into time added-on after receiving a second yellow card.

Fabio Quagliarella’s penalty double helped Sampdoria thrash Udinese 4-0.

Quagliarella struck from the spot in either half before Karol Linetty and substitute Manolo Gabbiadini added gloss to the scoreline as Samp moved up to sixth in the standings.

Sassuolo are up to ninth as goals from Manuel Locatelli and substitute Alessandro Matri either side of Khouma El Babacar’s spot-kick sealed a convincing 3-0 victory over Cagliari.