The incident came towards the end of the game between the two teams at the Club World Cup on Sunday.

"Following an assessment of the match reports, the FIFA Disciplinary Committee has opened proceedings against CF Pachuca player Gustavo Cabral in relation to the incident involving him and Real Madrid's Antonio Rudiger during the FIFA Club World Cup game played in Charlotte on 22 June," FIFA said on Tuesday.

Rudiger was visibly angered following an exchange of words with Argentine Cabral and spoke to Brazilian referee Ramon Abatti Abel.

Cabral denied he had racially abused the German centre-back.

Asked about the incident in the post-match press conference, Real Madrid coach Xabi Alonso said: "In football there is no tolerance for this, and if it happened, then measures should be taken. This is what Antonio has told us and we believe him. It's being investigated now".

Cabral, 39, spoke after the game and said his words had been misinterpreted by Rudiger.

The Argentine said he had called the defender a "coward", with the Spanish phrase he used similar to another which is linked to racist abuse.

"The referee made the racism sign but I was telling him the same thing the whole time -- (coward)," said Cabral.