Athletic Bilbao's Nico Williams scored against Atletico Madrid amid claims of racial abuse from sections of the home fans.
The Spain winger of Ghanaian descent attempted to draw the referee's attention to the alleged chanting, signalling for play to be halted.
Atletico players Antoine Griezmann and Jose Maria Gimenez were seen urging the home fans to cease chanting before the game resumed.
Despite Williams' goal cancelling out Rodrigo de Paul's opener late in the first half, Atletico ultimately secured a 3-1 victory with goals from Angel Correa and an own goal from Athletic goalkeeper Unai Simon.
Diego Simeone's side now holds a six-point lead over fifth-place Athletic with five games remaining, positioning them well for Champions League qualification next season.
Last month, Real Madrid complained to Spanish legal authorities after a video on social media allegedly showed Atletico fans chanting a racist slur aimed at Brazilian forward Vinicius Jr.