"You're a monkey, Vinícius, you're a monkey," chanted the supporters, according to an audio recording by radio station Cope, which said the Atlético Madrid supporter group included around a hundred people.
The background to the chant is said to be a statement from Pedro Bravo, head of the Spanish Football Agents Confederation, last Thursday.
In a TV interview, Bravo said that Vinícius Júnior needs to stop "behaving like a monkey" when scoring goals.
The statement, for which Bravo apologized and said it had no racist intent, created many reactions.
Vinícius Júnior and Real Madrid published statements condemning racism.
Atlético Madrid president Enrique Cerezo said on Sunday:
- What we need to do is make sure Vinícius doesn't score against us today.
If he does: May he celebrate in a proper way and with respect for the supporters.
Real Madrid won the match 2–1 without Vinícius Júnior being involved in any goal.