Floyd Mayweather has warned Conor McGregor his confidence will count for little once they are in the ring together.

The American’s 49-fight unbeaten record is on the line against mixed martial arts star McGregor, who will make his boxing debut at the T-Mobile Arena in Las Vegas on August 26.

Irishman McGregor has claimed he will win inside four rounds despite never having previously boxed as a professional or amateur.

The pair have traded insults during the promotional tour ahead of the bout but Mayweather appears ready for the talking to stop and the fighting to start.

“I’ve been here before and I know what it takes,” the 40-year-old said at a media workout at Mayweather Boxing Club.

“My opponent is always confident, but it’s different being in there with Floyd Mayweather. They realise that this is real.

“But for me, it’s just another day. That’s the mentality that has allowed me to stay undefeated.

“Conor feels it’s not going to go past four rounds and I don’t think it’s going the distance. We’re both confident in our skills and we’ll see who gets it done.”

Given McGregor’s non-existent boxing experience and Mayweather’s reputation as one of the finest fighters in history, many observers are predicting a mis-match.

But Mayweather is aware the duo will be expected to put on an entertaining show given the global attention the bout has garnered.

He said: “This isn’t just a fight. This is an event. We both owe the fans and everyone tuning in a lot of excitement. That’s what we’re there to give them.

Floyd Mayweather (John Locher/AP)(John Locher/AP)

“When it’s all said and done it comes down to the two competitors. My dad can give me a brilliant game plan but he can’t get in there and fight for me. Same for Conor and his team.

“It doesn’t matter who the crowd’s rooting for, it’s two men in there.

“On paper we know he’s taller and has a long reach. He has youth on his side. People say that he has power on his side.

“I know that ring IQ and experience are in my favour. I have the fight knowledge on my side. We both have advantages.”