Benfica investigate video of fans' monkey gestures
During Tuesday's match in Lisbon, Brazilian forward Vinicius accused Benfica's Argentine midfielder Gianluca Prestianni of racially abusing him.
Prestianni, 20, denies calling Vinicius a monkey and Benfica have stood by their player, claiming he was the victim of defamation.
European football's governing body UEFA has said it will "investigate allegations of discriminatory behaviour".
Portuguese media on Friday claimed that Benfica had begun their own investigation into the fans' behaviour.
"If they are club members...