Nathan Cleverly and Badou Jack came face to face for the first time in Las Vegas at a press call on Wednesday

WBA champion Nathan Cleverly says he will make Badou Jack "pay" for stepping up a weight division when he defends his world title on Saturday.

Light-heavyweight Cleverly, 30, will make the first defence of the belt he won from Juergen Braehmer, on the undercard of Floyd Mayweather's bout against Conor McGregor in Las Vegas.

Former WBC world champion Jack is stepping up from super-middleweight.

"He's coming up to my division, we are going to make him pay," Cleverly said.

'Weight jump could invigorate'

Cleverly, who has three defeats in a 33-fight career, performed his open workout at the MGM Grand on Wednesday. There were rumours among the press at the venue that he was not going to turn up.

It was thought he was keen to check on his weight rather than attend the event, perhaps suggesting he has work to do to make the 175lbs limit before Friday's weigh-in.

When he did arrive, the two-time world champion went through a repertoire of shadow boxing and pad work in a ring housed in a busy walkway in the hotel.

Nathan Cleverly participates in an open work-out in Las Vegas

Fans lined the ring but when Jack took his turn to workout, he did very little by contrast. The Swedish fighter has lost once in 24 fights and faces Cleverly after a draw at super-middleweight with Great Britain's James DeGale.

"Badou does the basics very well, a solid all-round fighter," Cleverly added. "He has a good guard, good defence and is a world-class operator who is consistent.

"He's had good wins over big fighters but he doesn't do anything exceptional. So he's a tough fighter but I think his style is suited to mine.

"I think he may feel stronger at the weight, and feel as though he has more energy. That extra bit of weight can invigorate you. He may be more confident and stronger. But I'm established at this weight for years and at some point in the fight you will see that difference."

'Floyd in six rounds'

Floyd Mayweather is seeking a 50th professional win and Conor McGregor will be fighting as a boxer for the first time

Cleverly admits he has been patient in waiting for this fight and claims he turned down a rematch with Braehmer because it lacked "spice" and "risk".

His reward is a bout which is chief support to the Mayweather versus McGregor bout which could become the richest in boxing history and surpass the record for pay-per-view buys.

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Cleverly gave both men credit for "capturing the imagination of fans," but maintains the meeting of a former five-weight world champion and UFC's McGregor, who makes his boxing debut, is a "fantasy event".

"You're looking at the best ever in Mayweather," he added. "He has mastered the art of boxing, hit and don't get hit. He's been in with the best in the world and they struggled to land a glove.

"For a martial artist to come in and hope to land a glove, let alone to become victorious, there's pretty much zero chance. But it's captured the imagination. It's a money spinner and fair play to the guys. I think Floyd in six rounds."