GEORGE GROVES insists he will upstage Floyd Mayweather when he fights on his undercard next weekend [September 12] to challenge Badou Jack for his WBC world super-middleweight title.

Mayweather fights Andre Berto at the MGM Grand in Las Vegas while Groves makes his third attempt at world honours, having twice lost to Carl Froch.

Having trained at the famed Big Bear camp in California, where middleweight king Gennady Golovkin is based, Groves feels he can better the main event in Vegas.

“People think it’s a 50/50 fight, we’re going to go in there and show them that couldn’t be further from the truth,” he said.

“We’re in a great place and we’re just ready to perform, steal the show, and arrive on the world scene.

Jack won the title from Anthony Dirrell in his most recent outing in April and Groves feels the Las Vegas-based Swede is still green.

“I’m in with a guy who is now world champion, making his first defence. He needs to learn how to be a world champion, it doesn’t just come with the territory, with the belt. You need experience, so he’s in a new situation.

“I feel I’m the best opponent he will have faced.

“I’ve climbed the top of the mountain, I just haven’t found my belt yet, but this time I’m not coming down without it.”

Groves also turned his attention to criticisms he has received over an apparent lack of stamina, with some detractors claiming he is not the fighter he once was after his losses to Froch.

A hard-earned decision victory over Christopher Rebrasse and a seventh round stoppage of Denis Douglin earned Groves his title shot, though some were left unimpressed with his performances.

“You’re never going to be as fresh in the first round as you are in the last,” he noted.

“But at the same time, I always finish strong. I’ve been 12 rounds before in high-intensity fights, fights which I’ve won, in which I haven’t faltered.

“It’s nice that a few people in the media, usually with an agenda, will say something, and then it catches fire and everyone jumps on it.

“Anyone who wants to base a game plan around me, around stamina, hoping that I’m going to fade and get tired… I’d never do that for any fight, because one day that guy isn’t going to get tired, and I’m certainly not going to get tired.

“I’m going to be full-steam ahead, from the first second to the last, and I’m really looking forward to it.”