The ex-England international witnessed the Juventus star’s development first hand at Old Trafford before he moved to Serie A in the summer of 2012.
|WORLD CUP SOCIAL HUB
|Keep up with all the latest news from Brazil and get involved in the debate on Twitter with our new World Cup Social Hub|
"Paul told me before he left that he wanted to be 'the best player in the world,'" the 35-year-old told BBC Sport.
"I don't know whether that will happen, but he will definitely turn out to be the best midfielder in the world.
"As well as his undoubted ability, his strength is definitely his self-belief, not just by statements like that but by how he backs them up.
"He made the big bold move to leave United, the best club in the world in my eyes, at only 19 because he wanted opportunities. He backed himself to do it, which is a big thing to do for a kid of his age, and he has not looked back since.
"You have to have that arrogance about you as a young player coming through at United, otherwise you sink. You won't make it."
Ferdinand also hinted at the real reason behind Pogba’s acrimonious departure from United, ahead of the Frenchman's possible return to the Premier League with Chelsea.
It was long thought that Pogba's omission from Sir Alex Ferguson’s side to face Blackburn in December 2011, the manager’s birthday, was the main motive for his departure and the former United captain confirmed that played a significant role.
Ferdinand said: "I think he left because he felt disrespected that he did not play in a particular game when a few players were played out of position in midfield."