Napoli were held to a 0-0 draw by AC Milan at San Siro in a boost to Juventus's Serie A title defence.
The Rossoneri had only beat Napoli once in 15 league games prior to this encounter but came close to improving that record, with goalkeeper David Ospina making some crucial saves.
Carlo Ancelotti's side had won their previous two top-flight games since losing on this ground to Inter Milan last month, but a relatively flat performance left them unable to worry Gianluigi Donnarumma's goal unduly and they lost Fabian Ruiz to a late red card.
Patrick Cutrone hit the side-netting in a bright opening spell from Milan, although neither side looked prepared to sit back and play for a point in a combative first 45 minutes.
Hakan Calhanoglu tested Ospina, while Piotr Zielinski and Jose Callejon each came close for Napoli without managing to hit the target.
Franck Kessie saw a shot deflected narrowly over the crossbar and Callejon clipped the woodwork with a cross, before Zielinski stung the palms of Donnarumma with a fierce volley.
New signing Krzysztof Piatek was introduced with 19 minutes left and almost made a telling impact within moments of entering the pitch, with Ospina bravely diving at his feet to deny him a debut goal.
Ospina, hurt by that collision, produced an even better stop to deny Mateo Musacchio's volley from the ensuing corner, the defender failing to convert after Piatek's header fell to him.
Zielinski shot straight at Donnarumma with a good late chance 12 yards out but, despite some frantic late defending from each side, Ruiz's second yellow card for handball in injury-time was the only incident of note.
What does it mean? Juve given title boost
The draw means Napoli will be 11 points behind Juventus if the Serie A leaders win at Lazio on Sunday evening (Monday morning AEDT). Such a gap would, at this stage of the season, look difficult to bridge.
It is not a result that hugely benefits Milan, either, as Roma will be able to knock them out of the top four if they win away to free-scoring Atalanta.
While a point apiece is by no means a dreadful outcome, neither team will be overly content.
Bold Ospina rescues result
There were few truly clear-cut opportunities in the match but Ospina produced two excellent saves from Milan's best openings, ensuring a share of the spoils.
Zielinski lacks killer touch
Zielinski looked the most likely to break the deadlock for the visitors but his finishing was not up to scratch. His shot that went safely into Donnarumma's grasp three minutes from the end was the best of his chances.
Napoli are back in action against the Rossoneri in midweek in the Coppa Italia quarter-final, before resuming Serie A duties at home to Sampdoria on Saturday afternoon (Sunday morning AEDT). Milan head to Roma the following day.