Vinicius Junior complained Sunday about an alleged racist act by stadium security aimed at one of his staff before the friendly between Brazil and Guinea in Barcelona.

The Selecao wore black shirts in the 4-1 victory at Espanyol's stadium on Saturday night, to protest against racial discrimination after Real Madrid winger Vinicius had been abused by Valencia fans, provoking global outrage in May. It was one of several incidents in which Vinicius was racially abused in Spain.

"While I was playing in the already historic black shirt and getting emotional, my friend was humiliated and mocked at the entrance to the stadium," wrote Vinicius on Twitter early Sunday.

"The treatment was sad ... to make everything public, I ask those responsible: where is the security camera footage?"

During a search at the entrance to the stadium, a security guard allegedly abused Vinicius' friend and advisor, Felipe Silveira, 27.

"Hands up, this is my gun for you," he is accused of saying, while taking a banana out of his pocket, according to an extract from the complaint filed by the player's friend, published by Brazilian news website Globo Esporte.

Silveira and three other members of Vinicius' staff complained and called police to the scene, the Brazilian website added.

Footage broadcast by Brazilian channel SporTV shows heated exchanges between the player's friends and staff at the stadium.

The guard and the security company denied the allegations, Brazilian media reported.

The Brazilian football federation (CBF) said they had taken action as soon as it became aware of the complaint and called on the police and match organisers to "give their full support and protection to yet another victim of racism, a crime that must be fought vehemently and relentlessly".

"Today, once again, another criminal has been publicly exposed," said CBF president Ednaldo Rodrigues.

Vinicius, 22, has been the victim of racist abuse on many occasions in the past two seasons.

Brazil decided the friendly was a good opportunity to strike back as the match was staged on Spanish soil.

In a powerful move, Brazil abandoned their iconic yellow and green shirts and were instead kitted out in an all-black strip in a stand against racism for the first half of the game.

The Brazilian Football Confederation was behind the gesture accompanied by the slogan of "Com racismo nao tem jogo" (With racism, there is no game).

Vinicius himself, wearing the number 10 shirt, got on the score sheet with an 88th minute penalty, by this time kitted out in Brazil's usual colours.

Earlier in the week the Spanish and Brazilian football federations presented their plan for a friendly match at the Santiago Bernabeu in March 2024 to combat racism following global outrage at the abuse of Vinicius.

World football governing body FIFA also announced plans to create an anti-racism taskforce in which Vinicius would have a "prominent role".