Head coach Carlo Ancelotti revealed Napoli tried to get their Serie A match against Inter Milan suspended because of alleged racist chanting against defender Kalidou Koulibaly.

With nine minutes left, Koulibaly was dismissed for sarcastically applauding the referee after a caution, and substitute Lautaro Martinez went on to score a late goal that handed Inter the three points.

Ancelotti said following the game Napoli had called for action in response to alleged taunts directed at Senegal international Koulibaly and that in future, his players would leave the field.

"It's a shame because twice we asked for the match to be suspended for the racist chanting towards Koulibaly," Ancelotti told the club's official website.

"It shook him – he's a good-mannered player and he was bombarded by the stadium. Despite our requests and the chanting, the game wasn't suspended. I think it should have been. Next time we'll stop playing ourselves.

"It was impossible for him to be calm – he cares a lot about the issue of racism and he commits a lot of time to the matter, including in society. What happened today is unacceptable – not just for us but for Italian football as a whole."

Koulibaly posted a message in Italian on his personal Twitter account following the match.

He said: "I'm sorry for the defeat and above all to have left my brothers! But I'm proud of the colour of my skin. To be French, Senegalese, Neapolitan: man."

The Partenopei had been aiming to make up ground on leaders Juventus, who had earlier battled to a 2-2 draw at Atalanta.

However, Napoli could not find a breakthrough  and Martinez had the final say following a breakaway.

As tempers boiled over during the closing moments, Napoli forward Lorenzo Insigne was shown a red card after tussling with Inter substitute Keita in an off-the-ball incident.

"The red card determined the result," Ancelotti added. "We were pushing towards the end but we were affected by going down to ten men.

"We could have scored in the last minute and therefore could have won the game anyway.

"Now we need to think ahead to Wednesday's match, where we can round off the year positively. Tonight's result doesn't change anything as regards our targets."

The build-up to the game had been dominated by the news Inter had allegedly temporarily suspended midfielder Radja Nainggolan for disciplinary reasons. The Belgian reportedly was at loggerheads with Inter head coach Luciano Spalletti.

Following his side's victory, Spalletti confirmed Nainggolan had been fined, but would return to the group ahead of the match against Empoli on Saturday.

"Radja we all wanted (in the team) because he has the right characteristics to give something more to our midfield, but he was out of a game because he did not behave correctly and in football there are rules to be respected," the Inter coach said, quoted on the club's official website.

"He has been fined, he will now rejoin the group and we will see if he will be available for the match against Empoli."

Third-placed Inter moved to within four points of Napoli and Spalletti felt his side were value for their dramatic victory.

"We deservedly won for the chances which we created, but it is true that if Kwadwo Asamoah had not left a bit of him on the line (to make a clearance), we could have lost it too," he said.

"It was a wonderful race, played by two teams which showed off good passing at speed."