Mata left Chelsea in January 2014 after Mourinho decided he wasn’t keen on the Chelsea fan favourite’s work-rate.
The 27-year-old has established himself as a key player for United this season and insists that he is much happier under new boss Louis van Gaal, who he says is far more appreciative of his contributions.
Mata told The Times: “I really value his honesty. When someone does something in training that he really likes, he goes over to hug and kiss them – he really does it.
“Or he says in front of everyone, you are the best in training, I’m really proud of how you played, to set a a good example to others.
“Van Gaal is how you see him in the press conferences, he’s like that with us too.
“He’s honest and straightforward. He believes in his style of training and way of preparing for games. He’s won trophies everywhere he’s been and hopefully this season now we know him better we’ll win something too.”
Mata has played a part in 45 per cent of the 25 goals United have scored this season and has already matched his tally of 18 Premier League goals for Chelsea in 26 fewer matches.
He added: “I’ve scored as many goals for Manchester United in the Premier League as for Chelsea, but in something like 30 games less.
“In terms of scoring and assisting and I’m quite happy with the stats, and stats don’t lie. They are facts.
“If a luxury player is a player who scores and assists and has good stats, then I’m happy to be a luxury player.
“I want luxury players in my team. I like creative players and players who do different things. It’s easy to say certain players are luxuries, especially when you’ve lost a game.”