(Reuters) - Recent actions by a billionaire owner of a National Basketball Association team and a supporter of a Spanish football club have offered the sporting world a stark reminder that racism knows no borders.
From the Staples Center hardwood in Los Angeles to La Liga's manicured pitches, and everywhere sport is played at the highest level, the murky undercurrents of racism flow from the stands and suites to the field of play.
On the same weekend a secretly-recorded racist diatribe by Los Angeles Clippers owner Donald Sterling sparked a firestorm of outrage across the United States, a Villarreal fan tossed a banana at Barcelona's Dani Alves as he lined up a corner kick.
Alves responded to the taunt by taking a bite of the fruit while the perpetrator was eventually arrested and banned for life.
The 80-year-old Sterling was also banned for life after his shocking remarks showed there were elements of bigotry even among owners of North American professional sports teams.
"We know that this exists," John Wooten, head of the Fritz Pollard Alliance Foundation, which monitors diversity in the National Football League, told Reuters. "This is why there are diversity inclusion committees in sports.
"These things exist because that stigma still stands throughout our culture, throughout our country.
"That is why you have to continually stand and fight and deal with it day after day. You have to meet it on all fronts because it comes from all areas."
Gambling, drugs and homosexuality have all been hot-button issues for North America's big four professional sports leagues but nothing has provoked more debate and inflamed passions than the suggestion of racism.
With sponsors fleeing and players in open revolt over Sterling's racist comments, NBA Commissioner Adam Silver moved quickly to quell the uprising by levying the harshest punishment available under his power.
In addition to the life ban, Sterling was also fined $2.5 million and told that he would have to sell the team he has owned for 30 years.
But while the NBA may rid itself of Sterling, the wider problem of racism exists, according to New York Times columnist William C. Rhoden, who often writes on racism in sports.
"We can focus on this, and they'll kill Sterling and declare racism dead and we can all go away," Rhoden said.
"We can say, 'All good, the Wicked Witch is dead. It's done. Racism is done. Let's all go, let's watch the games.
"I think what this has really done is taken the veil off it."
'WORK TO BE DONE'
From the gridiron to tennis courts, racism has manifested in many forms, both subtle and overt.
Despite protests, vigorous lobbying and even intervention from President Barack Obama, Washington Redskins owner Dan Snyder has vowed not to change the name of his National Football League team, considered offensive by many Native American groups.
Major League Baseball's Atlanta Braves and Cleveland Indians have also refused to bend to similar pressure.
Confederate flags, which to many Americans is an unsettling symbol of slavery and segregation, proudly flutter from motor homes at NASCAR races while the NFL is expected to introduce a 15-yard penalty for players who use racial slurs.
Serena and Venus Williams, two of the biggest names in women's tennis, continue to boycott Indian Wells, one of the biggest events on the sport's calendar, after their father claimed racial slurs were directed at him during the 2001 edition of the tournament.
Sport has often been on the frontlines in the fight against racism, Jackie Robinson breaking Major League Baseball's colour barrier in 1947 and Willie O'Ree doing the same in the National Hockey League in 1958.
But, despite decades of affirmative action, many avenues to good jobs remain blocked for minorities, forcing leagues to put in place hiring and educational programs.
With no minorities currently racing at NASCAR's top level, the series has developed a 'Drive for Diversity' program while the NFL requires teams to interview at least one minority for head coaching and senior football operation jobs.
Each season Major League Baseball celebrates Robinson's legacy by having players from every team wear his number 42 on Jackie Robinson Day with the purpose of educating fans about the Hall of Famer's accomplishments.
After Sterling's rant it was suggested on social media and in newspaper columns that if he wanted to avoid associating with black people he should sell the Clippers and buy a team in the NHL, which has the smallest percentage of African-Americans among the four major professional leagues in the United States.
In an attempt to reach out to minorities, the NHL developed a diversity program which is a major component of the league's "Hockey is for Everyone" initiative.
"Great, great things have been accomplished but there is still much work to be done," said Wooten, a former NFL player with the Cleveland Browns and Redskins. "I think we have to continue to work from that point.
"The whole thing about racism is lack of respect.
"I think NFL has done a marvelous job, baseball is doing better, I think what Adam Silver did was outstanding just in terms of taking a stand.
"I think the world will look at this and understand that this is the way this has to be dealt with."
(Reporting by Steve Keating in Toronto; editing by Frank Pingue and Julian Linden)