Jake Paul just released the ultimate flex on his haters ... dropping a rap video bragging about his massive wealth and success -- and he recorded the whole thing during Nate Diaz fight week!!
The Problem Child shared the visuals for his new track, "Witness," on Friday ... and he put his luxurious toys, boxing career and love life on full display.
The 3-minute project includes footage from fight week and highlights from his win over Diaz -- and as it turns out, Jake even recorded himself mouthing the words to the song inside the ring after the match.