Conor McGregor claimed he had won every round of his promotional tour alongside Floyd Mayweather but the UFC superstar was once again forced to defend himself against allegations of racism.

The claims levelled against McGregor first arose during the opening two legs of the four-date journey through North America and Europe to generate publicity for their 26 August clash when he told Mayweather "dance for me, boy" - a phrase that has racial overtones.

Before the two faced each other for a verbal tussle in the ring in front of a 10,000 crowd at SSE Arena, Wembley, undefeated former five-weight world champion Mayweather rounded on his rival.

McGregor, who has predicted he will win inside four rounds despite never having previously boxed as a professional or amateur, rubbished the suggestion he is a racist.

McGregor was by far the more popular when the two fighters arrived on stage in front of a packed Wembley crowd.

Cheered on by a swarm of supporters 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 venue 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 and endured a hostile reception from the pro-McGregor crowd throughout his performance, which 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, he repeatedly called him "quitter" and tapped the desk behind which he sat, but was repeatedly told to "sit down, shut up" by the crowd.

"The tour became a verbal battle that people were scoring and I didn't anticipate it being so back and forth," McGregor said.

"If we are going to score it then f*** it, let's do that - I smoked him on all four rounds. LA was a 10-9, my suit went viral, Toronto was a wipeout 10-7 because he was dropped twice. I won New York and then here I smoked him again. For a 40-year-old man he has his childish ways and that's amusing. This is a ruthless business and I am ruthless."

"One or two (days) were maybe close. But who garnered the most interest? who went viral multiple times? That was me. I brought many factors to it. I switched it up multiple times. I believe it was no contest.”