By Keith Idec

LAS VEGAS – Conor McGregor scoffed at the rumors that he is having difficulty making weight for his showdown Saturday night with Floyd Mayweather Jr.

The brash Irish star told a small group of reporters Tuesday afternoon that his supposed weight struggles amount to wishful thinking by Mayweather and anyone who believes he’s having extreme difficulty getting down to the 154-pound limit for their 12-round boxing match at T-Mobile Arena in Las Vegas.

“Tell him to shut his f***in’ mouth,” McGregor said after he and Mayweather made their ceremonial grand arrivals Tuesday outside T-Mobile Arena. “He knows nothing. Let him keep praying for weight, praying for fatigue, praying for me to take a back step. All he’s doing is praying, but he’s praying to the new God of boxing.”

McGregor insists that this training camp for his boxing debut has gone according to plan, including cutting weight in an effective fashion.

“Absolutely phenomenal, like it always is,” McGregor said. “Tell me one time I’ve ever missed weight or not performed. So let him think what he wants.”

The 29-year-old McGregor twice fought Nate Diaz at the mixed martial arts welterweight limit of 170 pounds last year. The strong southpaw has since moved back down to lightweight and added another UFC title to his resume (155 pounds in MMA).

The 40-year-old Mayweather has never weighed in at more than 151 pounds for any of his 49 professional fights. The boxing legend tends to add very little weight between when he weighs in and when he enters the ring for his fights.

McGregor expects to weigh around 170 pounds by the time he enters the ring Saturday night, much more than Mayweather (49-0, 26 KOs).

“I’ll be heavier,” McGregor said. “I’ll be a lot heavier than him. And make no mistake, he’ll feel every single pound.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.