Marcos Maidana (R), here punching Adrien Broner on the way to a dominant win on Dec. 14, 2013, is known for his power. Photo by Naoki Fukuda.

Oscar De La Hoya is among those who have come closest to defeating Floyd Mayweather Jr., though he lost his WBC junior middleweight titleholder to "Money" by split decision in May 2007.

De La Hoya addressed the difficulty of facing Mayweather (45-0, 26 knockouts) during a conference call on Wednesday, along with the No. 1 pound-for-pounder's defense of his RING and WBC welterweight championships on May 3 against hard-hitting WBA counterpart Marcos Maidana (35-3, 31 KOs).

"He's just slippery. Slippery to hit," said De La Hoya. "This is my experience, and I'm just talking for myself, obviously, with me being a competitor and having a fighting spirit. If I was younger, I would have beaten him, but that's just the way that I feel. But nobody has beaten him before or since. That's the reality. He's undefeated."

Maidana will give it his best shot at The MGM Grand in Las Vegas on Showtime Pay Per View, hoping to follow up December's unanimous decision over Adrien Broner, whom he floored twice, for the WBA title.

"With Broner, everyone thought that I couldn't win unless I knocked him out, but I'm prepared to go 12 rounds with him if necessary," said Maidana. "I am preparing to hurt him every time that I throw punches, and if the knockout comes, then great. But I am preparing myself to win up to 12 rounds."

Three of Mayweather's most sensational knockouts were accomplished against fighters who attacked: Genaro Hernandez, Diego Corales and Ricky Hatton.

"I guess that it's true about those who have tried to come forward against Floyd. But the fact is that Floyd never has faced a fighter with the power and the heart and the determination of Maidaina, who is one of those guys who is not worried about who is front of him. He's not worried about fighting the best fighter in the world, or the best fighter in history," said Maidana's trainer, Robert Garcia.

"He's not worried about anything. He gets ready to fight and to do what he does best, and he'll do that against anybody. He goes out there to try to hurt his opponent, and that's what he's training to do. He throws punches from different angles and has tremendous power in both hands. There's no secret to that. He has no respect for whoever is in front of him. He's not thinking about it. He feels like he can beat him and anybody else in history that's in the ring in front of him."