Jake Paul vs. Manny Pacquiao is a fight you will NOT see ... 'cause the Filipino legend tells us he's laser-focused on bolstering his legacy -- and a fight with the YouTube star doesn't help.
... but he didn't slam the door on Manny Pacquiao vs. Floyd Mayweather II.
TMZ Sports talked to the 42-year-old boxing great while he was training at Wild Card Boxing in Los Angeles ... and we asked Manny if he had any interest in boxing Jake.
"No, I will not. I will not. I want to fight the best to add on to my legacy."
Of course, 24-year-old Paul -- who's fighting ex-UFC champ Tyron Woodley later this month -- previously told us he had his sights set on ... the top pound-for-pound fighter in the world, CANELO ALVAREZ.
But, Pacquiao ain't interested ... but Jake shouldn't take it as a shot at his skills in the squared circle.
"I’m not underestimating Paul, but he’s, he doesn’t have a lot of experience of boxing. So, in that point, he’s already, disadvantage for him to fight in boxing."
FYI, Manny -- who's coming off wins against stars Adrien Broner and Keith Thurman -- has a huge fight against 31-year-old boxing champ Errol Spence on August 21 ... and clearly isn't slowing down despite his advanced age for a fighter.
We asked Pacquiao if he wanted a rematch with Floyd Mayweather ... so he could avenge his 2015 loss against Money.
Manny says he's down to do it (even though Mayweather's retired) ... adding Floyd is invited to the Spence fight.
Your move, Floyd.