The returning Pogba, who has only trained with United for 11 days, has been declared fit for selection against Southampton tonight when the Frenchman could make his first Old Trafford appearance since 2012.
A world-leading sum of £89m (€102m) was required to bring him back after a four-year stint with Juventus and Mourinho believes his club have acquired a player who has evolved into one of the planet’s finest midfielders.
However, the United boss does not expect to see Pogba breaking Messi and Ronaldo’s domination of the Ballon d’Or because his goal haul, which never exceeded 10 in a season at Juve, is not eye-catching enough.
“First of all, when you speak about the best players in the world you go immediately to the ones that score a lot of goals,” Mourinho said.
“You don’t give a gold ball to a goalkeeper. They gave a gold ball to (Fabio) Cannavaro once but because in that season he was captain of Italy, they were world champions, and there were not too many top players.
“(Paolo) Maldini never got a gold ball, (Javier) Zanetti never got a gold ball, top goalkeepers over history don’t get a gold ball. You look immediately to the ones that score a lot of goals.
“Can Paul score Ronaldo and Messi goals? Not even 25%. I believe in a season he cannot score 20 goals. If to be the best player in the world means to score a lot of goals, that’s not the point.
“He is one of the best midfield players, maybe I could say the best midfield player in the world.”
Much has been made of United breaking the world transfer record to sign a player they let walk away for virtually nothing when Alex Ferguson was in charge.
Mourinho expects Pogba would have developed into the star he is now had he remained at Old Trafford, though he praised the club for having the gumption to re-sign him.
“I know Sir Alex tried everything to give him a new contract,” Mourinho added.
“The decision was made between the player, his entourage, his agent. The way it works for them was a great decision. But I think it’s very important for the club not to be afraid to do what the club did. You lose a player, it doesn’t mean if you have the chance to recover him, you don’t recover him.
“Chelsea did the same mistake with (Nemanja) Matic and a few years later I pushed the club to do the deal. You did one mistake, why are you going to do the second mistake?
“You do the mistake only once.”
While Pogba’s time may come against Saints, fellow high-profile summer signing Henrikh Mkhitaryan has been restricted to a pair of substitute appearances so far.
Mourinho explained that was due to the options he wanted against Leicester and Bournemouth and insists that, unlike other managers, he feels little pressure to throw the former Borussia Dortmund playmaker in right away. “Some managers, when it’s their decision to buy players, the first thing they think is to protect themselves,” he claimed.
“To protect their choices, the player they buy, they have to play all the time. I’m not like this. Before me comes the team and what I think is best for the team.
“I keep saying Mkhitarayan is a super football player and will give us a lot during the season.”
Meanwhile, Matt Targett has warned his Southampton team-mates that a slow start tonight will prove costly.
Southampton started life under new manager Claude Puel with a 1-1 home draw with Watford last weekend, leaving Targett and his team-mates already ruing missed opportunities.
“The first half (against Watford) wasn’t good enough, and the manager said that at half-time,” Targett said.
“We know we can’t start the game like that against Manchester United, because it will be game over in 20 minutes.
“So hopefully we get off to a good start.”