Floyd Mayweather: Conor McGregor is a 'dirty' fighter

Floyd Mayweather has called Conor McGregor a “dirty” fighter having watched videos of the Irishman in sparring and claimed he is taking the biggest risk in their match-up because of his unbeaten record.

"I'm taking the biggest risk, but it is a big reward for both," said Mayweather, unbeaten as a world champion in five weight divisions over the last twenty years.

"I have the 49-0 record. If you have lost before it's OK,  but if you are 49-0, as I am, everything is on the line."

McGregor has lost three of his 24 mixed martial arts contests. This will be his first professional boxing match, one expected to draw five million pay per view buys and shatter all records as the richest fight in history, potentially grossing over 700 million US dollars

But Mayweather believes the UFC's Irish mixed martial arts star will employ potentially underhand tactics when they face off here in their mega-fight on August 26.

READ MORE:All you need to know about the Mayweather v McGregor $1bn superfight

And the richest boxer in history reiterated that this really will be his very last fight, after which he intends to tighten up his business interests for his family for "generations to come".

Mayweather watched clips of McGregor in training against former two weight world champion Paulie Malignaggi. "I see a lot of rabbit punches behind the head, grappling, wrestling, illegal shots,” Mayweather said on an international media conference call.

"Some may call that a KO (over Malignaggi), but it doesn't matter as it is just in the gym. What counts is in the ring. Paulie has retired and he is now commentating and traveling around the world. McGregor is active and hard in training."

“But the ref will be fair on both sides, I want him to be even. I want us to have a good solid fight.”

McGregor will receive severe financial penalties - contractually - if he employs anything beyond the skills of boxing as he does in the Ultimate Fighting Championship, in which kicks, elbows and knees can be employed, as well as choke holds.

McGregor has hired retired referee Joe Cortez to oversee his sparring, and that was not lost on Mayweather, who said he did not see Cortez stepping in when he might have in the sparring.

“I truly believe Robert Byrd is going to do his job, his job is to keep the bout clean,” Mayweather added. “We are going to have a hell of a fight. Like I have said, I am coming straight ahead."

“I look forward to following the Queensberry rules of boxing. McGregor had referee Joe Cortez in his training camp but I still see him being extremely dirty. But my job is not to referee the fight, I am going to do my job. I am not worried about the outcome, I am more worried about excitement.”

Mayweather had also said in recent television interviews that he may be prepared to fight McGregor in a rematch, perhaps even in a mixed martial arts fight, but was insistent that this will be his last walk to a fight ring.

“I thought Andre Berto (September 2015) was going to be last weigh-in, last training camp, my last everything,” Mayweather explained. “But you just never know what can happen and we are here with this big event. This is my last one, ladies and gentlemen. I gave my word to Al Haymon (his business and boxing adviser), my children, and I don’t want to break that. I want to stick to my word. This will be my last fight.”

"I now want my children to go to College, and do what I was never able to do," explained 40-year-old Mayweather. "They will be able to turn 100 million in my business into 300 million. I took risks to get here, and it has been a long journey."