Mourinho and Chelsea acquired a 21-year-old Salah from Basel for €16.5 million in January of 2014. However, the Egypt international found opportunities hard to come by at the club and was loaned to Fiorentina the following winter and then sold to Roma a year later.

Salah returned to the Premier League at the start of this season, signing with Liverpool for a then club-record fee of €42m, and has been a revelation for Jurgen Klopp's side, scoring 43 goals in all competitions and being named the PFA Player of the Year.

Speaking to ESPN Brazil, Mourinho acknowledged Salah's blossoming at Anfield.

"I think everything has surprised even him. It has been fantastic," the Manchester United boss said of Salah's breakout season.

"But he is a great player that has reached the peak of maturity, he has already lived several other experiences and now has fitted perfectly into the style of play of the team, of the coach and of the club as well. So it doesn't surprise me that much."

Jose Mourinho insists he was not responsible for selling Mohamed Salah to Roma in 2016. Getty Images

Salah is on pace to break Ian Rush's Liverpool club record for goals in a season and has recently vaulted into the Ballon d'Or discussion following a masterful two-goal, two-assist performance against Roma in the first leg of their Champions League semifinal on Tuesday.

Salah's sensational campaign has left many to question Chelsea's decision to sell him, and Mourinho defended himself from those queries, adding: "It is the first time that I am going to say this, but it is another injustice that has been talked about me.

"People say that I was the one that sold Salah and it is the opposite.

"I bought Salah.

"It is the opposite. I was the one that bought Salah. I was the one that told Chelsea to buy Salah. It was with me in charge that Salah came to Chelsea. But he came as a young kid, physically he was not ready, mentally he was not ready, socially and culturally he was lost and everything was tough for him.

"We decided to put him on loan and he asked for that as well. He wanted to play more minutes, to mature, he wanted to go and we sent him on loan to Fiorentina, and at Fiorentina he started to mature.

"Chelsea decided to sell him, OK?

"And when they say that I was the one that sold him it is a lie. I bought him. I agreed to send him on loan, I thought it was necessary, I thought that Chelsea had wingers... Some of them are still there like Willian, [Eden] Hazard and all those players already in a different level.

"So the decision to send him on loan was a decision we made collectively, but after that, the decision to sell him and to use that money to buy another player wasn't mine. But even if it was, in football we make mistakes a lot of times, so many times some players develop in way we were not expecting, some other don't reach another level like we thought they would, so I don't even think this is a mistake, it is just part of the job.

"But effectively I did buy Salah, I didn't sell Salah, but it doesn't matter. What matters is that he is a fantastic player, and I am really happy for everything that is happening for him and especially because he scores against everyone and he didn't score against us in two games."