Nico Williams of Athletic Bilbao scored during their 3-1 La Liga loss at Atletico Madrid after alleging that a group of home supporters racially abused him.
The Spanish winger requested that referee Juan Martinez halt the match partway through the first half at Estadio Civitas Metropolitano.
The match was temporarily stopped to address the crowd with an announcement, and Atletico Madrid players Antoine Griezmann and Jose Maria Gimenez were seen appealing to their fans to cease the offensive chants before the game continued.
“I have gone to take a corner and I have heard monkey sounds,” 21-year-old Williams told DAZN.
“There are stupid people everywhere, but nothing happens. We have to keep working.
“I hope this changes little by little because in the end we are fighting internally and externally against this.”
Williams was booed by some fans throughout, which intensified when the match was stopped and after he equalised just before half-time.
Talking about his goal celebration, he said: “It comes with a bit of anger.
“It is not normal that they still insult you because of your skin tone.”
Williams’ brother and team-mate Inaki Williams said: “The jeers should be directed at the people who said the insults and not at the victim.”
Writing on social media, Atletico said the club were “against any act of racism or hatred”.
A La Liga statement read: “There’s no place for racist or hateful behaviour in sport.
“La Liga vehemently condemns any racist acts and will continue working to eradicate this inexcusable behaviour from our sport.”
Williams equalized after Rodrigo de Paul had opened the scoring, but a goal from Angel Correa early in the second half and an own goal by Athletic goalkeeper Unai Simon secured the win for Atletico Madrid.
With five games left in the season, Atletico is now six points ahead of fifth-placed Athletic, putting them in a strong position to qualify for Champions League football next season.
Last month, Real Madrid lodged a complaint with Spanish legal authorities following the emergence of a video on social media that appeared to capture Atletico fans chanting a racist slur directed at Brazilian forward Vinicius Jr.