Never missing an opportunity to flash his formidable muscles as a salesman, Floyd Mayweather did his best to sell Conor McGregor's chances in their Aug. 26 boxing pay-per-view match on Tuesday, saying, "I'm not what I used to be." 

During a sit-down interview with ESPN's Stephen A. Smith at his Las Vegas gym, the 40-year-old Mayweather talked up the size, youth and talent of McGregor, 29, the UFC's 155-pound champion, who will be making his pro boxing debut. 

"I'm older. I'm not the same fighter I was two years ago," Mayweather said. "I'm not the same fighter I was five years ago. I lost a step. A fighter like Andre Berto isn't even supposed to go the distance with Floyd Mayweather, but remember, I was 38. It's obvious, I'm slipping a little bit to even let a fighter like that go the distance with me."

Mayweather (49-0, 26 KOs) was referencing his last in-ring appearance, a September 2015 victory over Berto. Shortly after the bout, Mayweather retired for two years, maintaining all along he had no plans on coming back. 

Pushed by Smith to clarify whether an older version of Mayweather would still prove too experienced for a novice opponent, Mayweather hedged his comments just a bit by saying, "I didn't say I couldn't fight. I just said I'm not the same Floyd Mayweather I once was."

Yet following a four-city international media tour last month in which Mayweather spent the majority of time discrediting McGregor's chances, focusing largely on the MMA star's three submission defeats, Mayweather changed his tune this week. 

"He's a lot younger. When you look at myself and Conor McGregor on paper, he's taller, has a longer reach, he's a bigger man from top to bottom," Mayweather said. "He's a lot younger, so youth is on his side. And I've been off a couple of years. And I'm in my 40s. So, if you look at everything on paper, it leans toward Conor McGregor."

The transparency of Mayweather's sales pitch was clear for anyone who has followed his career and is used to hearing him put over the chances of another "hungry young lion" before entering the ring and surgically disarming them for 12 rounds. This time, Mayweather even took a shot at his own punching power, referencing the six-year gap since his last knockout against Victor Ortiz.

"I used to have a 90 percent knockout ratio," Mayweather said. "It's obvious I slipped somewhere. Something has taken a toll on my career."

Despite putting down his own ability to finish fights in one breath, Mayweather somewhat predictably contradicted himself shortly after by assuring fans he plans on going after McGregor and finishing him.  

"This can't be a defensive fight. I have to go to him," Mayweather said. "I owe the public because of the [Manny] Pacquiao fight. They weren't pleased with that. They're gonna be pleased with this fight here."