A two-division champion within the Ultimate Fighting Championship, Conor McGregor has never lacked for confidence, and that is a trend that has continued for his latest bout, albeit in a different sport than the world of mixed martial arts.

McGregor will step out of the UFC’s famed Octagon and into a boxing ring to face off against 12-time world champion Floyd Mayweather Jr. in a scheduled 12-round bout at T-Mobile Arena in Las Vegas on August 26 with the same confidence that made him a champion in MMA.

“I’m going to knock him out inside four rounds, mark my words,” McGregor said during the four-city press tour to promote the bout.

“He will be unconscious in under four rounds. The movement, the power, the ferociousness, he has not experienced this. He has fought people who have shied away from him. I don’t fear him. I don’t fear this limited set of fighting. This is a limited set of rules that makes this half a fight, a quarter of a fight. This isn’t a true fight. If this was a true fight, it wouldn’t even take one round.”

Last November, McGregor came to Madison Square Garden in New York City looking to make history and become the first simultaneous two-division champion in the history of the UFC, and that is exactly what he did.

Courtesy of a knockout of Eddie Alvarez in the main event of UFC 205 at "The World's Most Famous Arena," the 5-foot-9, 155-pound McGregor added the UFC lightweight championship to his resume, going along with the featherweight title he won in December of 2015.

While taking a right-handed punch from Alvarez, McGregor fired off a powerful left hand that landed on the side of the defending champion’s face. McGregor followed it up with a right hand to Alvarez’s jaw, a left to the ear and another right that eventually floored his opponent.

Once Alvarez was on the mat, McGregor landed two left-handed punches, and that forced referee “Big” John McCarthy to call a stop to the bout at the 1:52 mark of the second round.

“I’m a young, confident, happy man that has worked extremely hard for this,” McGregor said. “I have worked very, very hard for this, so I’m am just embracing everything. Nobody’s going to do and nobody can do anything to me. I can do whatever the (heck) I want. I’m just enjoying myself and having a good time.”

Crossover bouts in combat sports rarely happen between boxers and MMA practitioners, but McGregor wanted the match, and was willing to risk the transition by going into the boxing ring because of his success of punching out his opponents in the cage.

Of McGregor’s 21 professional MMA wins, 17 have come via knockout or technical knockout, and 16 have come as a result of punches.

“There’s been a few times in history where guys have crossed over,” McGregor said. “Muhammad Ali fought Antonio Inoki in Japan many years ago under MMA rules. He thought at the time it was a wrestling contest, but that wasn’t like this.

“Then, James Toney, who had a very big problem with the sport and a very big problem with the UFC, very similar to the way Floyd has, he crossed over into our world. Floyd has a problem, but doesn’t want to come over and deal with it. He wants me to come over to his side. That’s no problem. I’ll do that. That’s confidence.”