Mata previously worked with Mourinho at London club Chelsea but the two couldn’t see eye to eye and he was sold to David Moyes’ United.
Many fans were delighted with the Spaniard’s arrival but knew that Moyes’ only bought him to try and rescue his own career at Old Trafford.
Louis Van Gaal was next to sit in the hot seat and shifted the player out to the right flank, seeing him as incapable to playing the attacking midfield role in the Premier League.
Jose was next to arrived and many believed this would spell the end of the former Valencia man’s time at the Red Devils but the player insisted he though otherwise.
According to the Express, Juan said to FourFourTwo: “What was I thinking? Firstly, that I had no kind of personal problem with him, no matter what the press said.
“And secondly, that I wanted to show what I could bring to the team, to prove myself. That was the important thing, to do your talking on the pitch.
“It’s a challenge in my career that I’m proud to have confronted head on.”
It’s fair to say that since that moment of uncertainty the two men have enjoyed a relatively neutral relationship that hasn’t turned sour since.
In fact, Juan Mata featured for Manchester United last season far more than most people anticipated he would.
It’s a credit to the Spaniard that he forced his way into Mourinho’s plans, becoming the player the manager often relied upon for good performances.
Jose’s love for traditional wingers though has sort of seen Mata’s influence decline this season, especially since his form has dropped off a little.
Typically a player who would guarantee you a seven out of ten performance, Juan has been a little inconsistent this time around and fans will be hoping his performance vs CSKA Moscow will help spark some better form.