Boxing coach Freddie Roach has been offering a reward of $1,000 to any sparring partner who could knock down Manny Pacquiao.
But none so far has succeeded.
"Manny doesn't know that! I've always kept it a secret but every sparring partner I hire, I say, 'You knock him down, I give you a thousand bucks'," Roach said in an article posted by The Sun.
"And I've kept a thousand in my pocket."
Pacquiao is currently preparing for his pay-per-view showdown against IBF and WBC welterweight king Errol Spence Jr. on August 21 at the T-Mobile Arena in Las Vegas, Nevada.
The 42-year-old boxing superstar will have his biggest challenge against Spence, a fighter taller and 11 years younger than Pacquiao.
Spence, however, refused to acknowledge his advantages. He attributed Pacquiao's longevity to the Filipino fighter's self-discipline.
“That’s why he’s been the same Manny Pacquiao for all these years and decades 'cuz, you know, he’s a guy that takes care of his body and, you know, stay disciplined, like he said," said Spence in Boxing Scene.
"So, and that’s what I’m looking for. I’m looking for the Manny Pacquiao that fought Keith Thurman, the Manny Pacquiao before that. So, that’s why I’m gonna train and I’m gonna train hard.”