UEFA said on Wednesday it would "investigate allegations of discriminatory behaviour" after Real Madrid forward Vinicius Junior accused Benfica's Gianluca Prestianni of racially abusing him during a Champions League match in Lisbon.
Tuesday's first leg of the knockout phase play-off tie was stopped for more than 10 minutes after Vinicius complained to French referee Francois Letexier about the alleged abuse following a confrontation between him and Prestianni.