Serie A on Thursday ordered Inter Milan to play two matches behind closed doors after club supporters allegedly engaged in racist chants against Napoli player Kalidou Koulibaly during a contest this week at the San Siro.
The league also handed down two-match suspensions to Koulibaly and teammate Lorenzo Insigne, who were both ejected from Wednesday's match for clashing with the referee.
A fight between Inter and Napoli fans before the match ended with four people stabbed and one hit by a van and killed.
Later, inside San Siro stadium, Inter fans yelled inappropriate remarks at several players, among them Koulibaly, who is from Senegal.
The incidents were condemned by several figures from the soccer world, and Serie A chief Gaetano Micciche said such situations will not be allowed to happen again.
Micciche said in a statement that he would study measures to eradicate racist and discriminatory chants from matches.
Napoli coach Carlo Ancelotti was fuming after the match about the abuse directed at Koulibaly.
The visitors asked on three separate occasions for play to be suspended, the coach said.
"The next time we'll stop playing, even if we lose the match," Ancelotti said.
Inter released a statement calling for respect and inclusion, saying that the 110-year-old club has always been committed to building "a future without discrimination."