Floyd Mayweather has accused Conor McGregor of making a series of alleged racial slurs that included insults directed at his family.
Mayweather rounded on his rival at Wembley Arena in the final leg of their four-date world tour to promote their boxing bout at the T-Mobile Arena in Las Vegas on August 26.
McGregor is alleged to have made the comments in the early hours of Friday morning during the third stop of the tour in New York.
“I respect every country. Racism still exists. It’s all about treating people like you want to be treated. To get respect you must give respect,” Mayweather said.
“He totally disrespected black women. He called black people monkeys. Then he spoke disrespectfully to my mother and he spoke disrespectfully to my daughter.
“I’m not going to stoop that low and speak about his like or speak about his child. I’m glad that he just had a healthy child and he has a beautiful family.
“There are certain levels you don’t stoop to and certain levels you just don’t go to. I love everybody from all walks of life.”
The claims of racism levelled against McGregor first arose during the first legs of the tour in Los Angeles and Toronto when he told Mayweather “dance for me, boy” – a phrase that has racial overtones.
And in trying to diffuse the situation when on stage at the Barclays Centre in New York, the UFC lightweight champion only inflamed it.
“All of the media seem to be saying that I am against black people. But do they not know that I am half black? I’m half-black from the bellybutton down,” McGregor said.
On a chat show after the New York event, he then appeared to refer to black people as “dancing monkeys” when discussing the film Rocky III.
MMA superstar McGregor has vowed to dispatch his rival inside four rounds of the contest but, while the money generated is expected to eclipse Mayweather’s victory over Manny Pacquiao, its credibility has been questioned.
McGregor, who turned 29 on Friday, has never boxed before at either professional or amateur level and is facing a five-weight multiple world champion regarded as the finest fighter of his generation.
“They call that jealousy. It comes with the territory. This is big for both MMA and the boxing world. This is huge,” Mayweather said.
“Every MMA guy is trying to fight a boxer. A fight like this can only happen once in a lifetime. This is a very, very big event.
“It took more than just myself to make this fight happen, but to make a fight of this magnitude happen I had to be involved.
“He can fight and he’s tough, but he’s also an entertainer. I like the fact he’s confident and we need more guys like him.
“We need more guys like the young Pretty Boy Mayweather, like McGregor, who are aggressive towards each other. That’s what we need in combat sports.”
McGregor was by far the more popular when the two fighters arrived on stage at a packed SSE Arena, Wembley.
Cheered on by a 10,000 crowd, whose spirits were not dampened by a near-two-hour delay to proceedings, a suit-clad McGregor goaded the 40-year-old with taunts about his age, bald head, tiny hands and tax bill.
He remarked that four years ago he had fought in front of only 400 people at a small hall venue nearby in London, adding “this is my first time in a boxing ring and in six weeks I’ll rule boxing”.
Mayweather was booed as soon as he took the microphone, enduring a hostile reception from the pro-McGregor support throughout, and his speech featured heavily on the MMA fighter’s record of having tapped out three times in his career.
Happy to perform the role of pantomime villain, Mayweather repeatedly called him “quitter” and tapped the desk behind which he sat, but was repeatedly told to “sit down, shut up” by the crowd.