After an ill-tempered derby match between Real Madrid and Atlético Madrid on Wednesday night, Marcelo, Real's Brazilian defender, was subjected to racist chants from the Atlético fans that remained in the stadium.
The away supporters were kept in the ground after the final whistle while Real's fans filtered out, a common policy in matches across Europe to prevent trouble outside stadiums. Real Madrid's unused substitutes, with Marcelo among them, took to the field for a short training session with the Bernabéu empty other than the small pocket of Atlético fans in the upper tier.
Monkey chants began to rain down on the field, according to eye-witness Graham Hunter of British broadcaster Sky Sports, who was in the press seats at the time. Worse still, after the session Marcelo's son went onto the field to hug his father, prompting chants of "Marcelo is a monkey," "Marcelo's not your father" and "we hope your father dies."
Neither Real Madrid nor Atlético has yet made any comment on the matter and no investigation has been announced.
"We hope your father dies" chanted Atlético fans when Marcelo's son went onto the pitch
Spain has a checkered history of casual racism at soccer matches. Several players have been subjected to abuse, including Samuel Eto'o, who started to walk off the field in a league match against Zaragoza in 2006 when monkey chants were directed at him. He was persuaded to remain on the field by other black players on his team, Barcelona, and among the ranks of Zaragoza.
"I'm black too," Zaragoza's Ewerthon, also a Brazilian, said after that match. "I'm a Zaragoza player, and totally opposed to the fans who did this. I've been abused at other grounds in Spain, but we need to rise above this. We all heard it. And if he [Eto'o] leaves, then I go as well."
In 2004 a friendly match between Spain and England at the Bernabéu was marred by racist chanting toward England players Shaun Wright-Phillips and Ashley Cole, which prompted a letter of apology from the Spanish government to its British counterpart and a fine of 65,000 euros for the Spanish Football Federation.
Also audible on Wednesday nights were chants directed at Atlético's naturalized Brazilian Diego Costa, who may play for Spain in this summer's World Cup.
Racism is rife in football stadiums across Europe, and Italy and Russia in particular suffer from similar problems. A Zenit St. Petersburg supporters' group wrote an open letter to the club in 2012 demanding that gay and black players be excluded from playing for the side. Russia hosts the World Cup in 2018.
In Italy last year AC Milan walked off the field in a friendly match in protest against racist abuse
In Italy last year, AC Milan responded to racist chanting during a friendly match against fourth-tier Pro Patria by walking off the field mid-game.
Although racism in stadiums in Britain has been all-but eradicated, several players have been caught out by the television cameras. A high-profile case involved Chelsea captain John Terry, who was charged with racially abusing Queen's Park Rangers player Anton Ferdinand. The case went to court, where Terry was cleared, but the FA found him guilty of abuse and banned him for four games and fined him 220,000 pounds. Luis Suárez of Liverpool was banned for eight games in 2011 for using racist language against Patrice Evra of Manchester United.
Uefa and Fifa, the European and world governing bodies for the sport, run regular campaigns against racism in soccer.