Lazio's match with Napoli was halted for around three minutes after sections of home supporters aimed abuse at visiting defender Kalidou Koulibaly at the Stadio Olimpico.
The game was stopped in the 68th minute when a section of supporters repeatedly booed Koulibaly when he was in possession.
In Italy, stiff 'anti-discriminatory' laws mean that league officials can temporarily halt or even end games prematurely if certain insulting behavior is not brought under control.
Referee Massimiliano Irrati only decided to continue the game after consulting with coaches of both sides and officials.
Koulibaly described the chanting as "ugly" and praised the referee for taking action on his Instagram account after the match.
"This is an important victory! But tonight I want to thank everyone for the messages of solidarity, but above all I want to thank the referee Irrati for his courage. I thank my team-mates, the club and our fans who have been a great support against these ugly choirs! Let's go ahead and force Napoli forever!"
Lazio manager Stefano Pioli was keen to play down the incident and, despite admitting he would not have stopped the game if he was officiating, did not believe the chants were racist.
Pioli told Premium Sport: "Obviously, these chants are not good, people need to be civil and show respect. But I don't think they were racist in nature, even we have black players.
"There was some kind of confusion. I'm not trying to excuse what happened, but we're giving too much importance to a minority. We also have players of colour and they are treated well."
Napoli boss Maurizio Sarri also praised the referee for his decision on Twitter. He said: "Bravo to Irrati for stopping the match."
Napoli went on to secure a 2-0 win, with goals from Gonzalo Higuain and Jose Callejon, to stay top of Serie A.