Real Madrid scorer Aurélien Tchouaméni was racially abused by a home fan in Saturday's 1-0 win at Real Mallorca, who have condemned the incident and contacted the police.
The incident, the latest to hit Spanish football and a Madrid player, took place after 24-year-old France midfielder Tchouaméni scored the winning goal with a long-range shot in the 48th minute.
"RCD Mallorca does not and will not tolerate any racist comments," the club said in a statement on Sunday. "We are actively involved in all campaigns to eradicate this scourge, which goes beyond sport."
But with an eye on possible punishments, the island club added: "May an isolated incident not tarnish the respect and sporting spirit of Mallorquinismo."
Real Madrid's Brazilian Vinicius Júnior, one of the most prominent and frequent victims of racist abuse in LaLiga, has repeatedly called for perpetrators to be sentenced to prison.
Following the victory in Mallorca, Real Madrid remain eight points ahead of defending champions Barcelona after 31 of 38 rounds.