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.