Reigning WBC welterweight champion Victor Ortiz has vowed to inflict a first career defeat on Floyd Mayweather when they clash on Saturday night in las Vegas.

Mayweather, a six-time and five division world champion, has a perfect record in 41 pro fights - with 25 KOs - which he is putting on the line against an opponent 10 years his junior.

Ortiz is brimming with confidence and insists, as world champion, he is the fight's draw card.

"Let's not forget I am the current champion of the world and I will remain champion," he said as they squared up at a Thursday press conference.

"Forty-one of those fighters [defeated Mayweather opponents] were not me. Forty-one of those couldn't move like me.

"I am going to teach you what it's like to have a loss on your record.

"Somebody's scared, but I'm going to hold my hands up and I'm going to put you on your ass."

Mayweather's repsonse was to the point as he vowed to put another stoppage on his record.

"I'm going to go in there with class and will leave there with class," he said.

"Victor Ortiz said the fight won't go the distance. So I say ok, it won't go the distance.

"I don't have to brag, I don't have to boast. I'm going to go in there and execute the game plan.

"[To Ortiz] You're an amazing athlete. I know you're going to bring your best. Let's give the fans what they want to see."