Vinicius condemns racist chants before Atletico Champions League game
"I hope you have already thought about their punishment," the Brazilian said on X, mentioning the official accounts of the Champions League and European football's governing body UEFA.
In his message, he relays a video where Atletico supporters can be heard chanting racist abuse on front of the Metropolitano stadium in Madrid.
"It's a sad reality that happens even during matches where I am not present," Vinicius added in the same message.
The Brazilian international has faced racial abuse since he joined Real in 2018.
The Spanish football league told AFP that it was going to lodge a complaint for these "lamentable racist chants", even if the incidents occurred during a European match, rather than the league, and outside the stadium.
"LaLiga is very committed to making football a hate-free space and will continue to relentlessly pursue any attitude of racism, homophobia, violence, hatred... whatever the competition," it said.
Atletico Madrid beat Inter Milan on penalties to reach the Champions League quarter-finals after Memphis Depay's late strike secured a 2-2 aggregate draw on Wednesday.