Real Madrid full-back Marcelo says he remains unaffected by racism following the derby win over Atletico.
Atletico Madrid fans allegedly shouted abuse at the Brazil defender, 25, after his side's 3-0 victory in the Copa del Rey semi-final first leg.
He wrote on Twitter: "Even though this is not the first time it happens I can promise you that we are stronger than any kind of racism.
"This will never affect me or my family."
In 2011, Uefa launched a disciplinary case against Barcelona midfielder Sergio Busquets over alleged racism against Marcelo, although the Spain international was cleared.
Atletico were ordered to play a Champions League match against PSV in 2008 behind closed doors after crowd trouble and allegations of racist abuse during a game with Marseille.