Floyd Mayweather has warned Errol Spence Jr not to take Manny Pacquiao lightly ahead of their clash of the ages on August 21.

Unbeaten American Spence Jr (27-0, 21 KO's) defends his WBC and IBF titles against eight-division world champion Pacquiao in Las Vegas, Nevada, and goes into the fight as an overwhelming favourite with the bookmakers.

It's the 31-year-old's first bout since he defeated Danny Garcia in December 2020. 

But speaking to reporters earlier this week, 44-year-old Mayweather Jr, who outpointed the former 147lbs world titleholder in May 2015, has urged Spence to take Pacquiao seriously.

As 'Pretty Boy' sees it, he feels the 42-year-old still has plenty left in the tank. 

"He [Pacquiao] is very dangerous still," Mayweather said (via BoxingNews24).

Mayweather decisively beat Pacquiao over 12 rounds in May 2015 to end the debate which had raged on for many years. 

However, he recently named the legendary Pac Man as the toughest opponent he has ever faced in his career. 

Teofimo Lopez, like Mayweather, has also preached caution to his fellow American, noting that Pacquiao has more experience operating at a higher level of competition, which could turn out to be a big factor on the night. 

"Anything can happen, and Pacquiao has had a long rest too," Lopez said (via BoxingNews24). "I like both guys in that fight, and may the best man win, really.

"Manny has so much experience; he can get through anything.

"As long as they have the right plan, whatever they do, they’ll have that. They’ll be able to do all that."

Despite Lopez's admiration for Pacquiao, however, he refused to dismiss Spence's talents. 

"However, Errol Spence, you can’t take anything away from Errol Spence," he added. "He’s still young, he’s in his prime, and he knows how to place body shots.

"He’s very strong at that; he’s like a body snatcher."

Read more: Isaac Lowe opens up about his friendship with Tyson Fury as he fires warning to Jordan Gill