The United boss revealed that he faced huge competition from “another big club” in completing the most noteworthy transfer of the summer.
Zinedine Zidane’s Real Madrid were interested in Pogba but were unwilling to match the fee the 20-time English champions were offering to Juventus.
“Oh! It was hard to convince him,” Mourinho told Goal. “I had many [conversations] on the phone, lots of SMS.
“I think he was getting one in the morning from the manager from another big club and one in the afternoon from myself. I had to try hard to convince him to choose us instead of the other one.”
United may be without top-level European football this season – with Mourinho instead leading his side into the Europa League – but the 53-year-old believes that both the Champions League and Manchester United themselves are suffering because the three-time winners are not competing in it.
“The Champions League without Manchester United is not the Champions League and Manchester United without the Champions League is not Manchester United,” he said. “So this is the first big step.
“But to get back to the Champions League we need to do well in the Premier League, so the first step is to recover the self-esteem, which I think we are doing.”
Following their success in the summer transfer window, with Mourinho masterminding the arrivals of Pogba, Zlatan Ibrahimovic, Henrikh Mkhitaryan and Eric Bailly, United made a strong start to the Premier League season before suffering defeat to Manchester City in Saturday’s derby.
While warning against expectations reaching unrealistic levels, Mourinho admits to being already impressed with the attitude of the squad at his disposal.
“I have a very positive feeling,” he said. “Rome was not built in one day and a football team is probably more difficult to build than Rome was!
“The feeling is that they want to work for me, they have the same level of ambition and commitment that I have and step by step, by a tactical and mental point of view, I have great feelings with the answers they are giving. So yes, I am very positive.”
Mourinho was known to be interested in the United job when Sir Alex Ferguson retired in 2013 but instead joined Chelsea for a second spell in charge at Stamford Bridge. However, the Portuguese is now enjoying life in the home dugout at Old Trafford following visits as an opposing manager for more than a decade.
“It feels like I am at home,” he said. “I didn’t feel strange or under pressure. I am enjoying the situation very, very much so I think we can both – me and the club – enjoy this professional relationship.
“For me I played so many times at Old Trafford as an opponent and – winning or not winning – I enjoy so much the atmosphere and the stadium.
“You can imagine that being at home with that amazing support behind the team is a moment to remember as one of the nicest ones in my career.”
Mourinho admits the club have taken backward steps since the departure of Ferguson having failed to add to their collection of league titles and missed out on the Champions League in two of the three seasons since he left.
“The past three years Manchester United went a few steps back and in football it’s not just [as if] everything clicks,” he said. “The biggest example is that we’re not playing Champions League.
“[The goal is] to have a certain style of football, a certain way to be in the competition which gives the fans empathy with the team and players, which we are getting.
“Then, we go for the results. We had a good start but it’s a long marathon. Bad results will arrive for sure, but let’s see how it happens.”