The 53-year-old, following a rocky start that entailed plenty of chopping and changing, has struck the right balance at Old Trafford, with his side claiming nine successive victories – their best record since 2009.
A win against second-placed Liverpool on Sunday would see Mourinho’s men move to within two points of Jurgen Klopp’s side.
And Mata, speaking earlier this week, noted that the Portuguese has cultivated a renewed sense of belief at Old Trafford.
“He has changed,” Mata noted when asked whether the boss’ attitude had altered since his spell at Chelsea.
“It is a different environment, it is a different club and squad. This club has always known that they play one kind of football which is about attacking and creating chances. We are doing that and he is happy with the performances.
“Everyone can see the players are playing with more confidence. He is the same person, with almost the same staff, but what has changed is the environment.
“It is nine wins is a row now and in terms of results, it’s the best I have known at Manchester United. In terms of the confidence and mentality we are showing it is also the best time since I have been here.”
Mourinho inherited a group of players still reeling from a traumatic 2015/16 campaign under Louis van Gaal. The Dutchman’s influence was emasculating: nobody could express any sense of individualism; nobody could do anything other than follow his outdated, restrictive and ultimately doomed-to-fail approach.
But the 53-year-old, bit by bit, has healed the scars of last season and, with four world class additions thriving at the forefront of proceedings, replaced them with a veneer of ruthlessness and dynamism. The squad has bought into Mourinho’s approach more than they ever bought into what van Gaal tried to implement, and United fans will hope to see their side continue to move in the same direction as the months go by.