At 31 and approaching 600 professional games, he can accept the groans after a misplaced pass or a damning verdict after a disappointing result -- Manchester United have had a few in the five and a half years the Spaniard has been at Old Trafford -- but in a week that has seen two teammates, Paul Pogba and Marcus Rashford, racially abused on social media because of missed penalties, Mata is concerned how footballers are being targeted.

He has seen Raheem Sterling criticised for speaking out about racism; the same with Danny Rose about mental health or Hector Bellerin on environmental issues; USWNT star Megan Rapinoe endured a torrent of online abuse after a public spat with U.S. president Donald Trump during this summer's World Cup.

Mata has used his platform to highlight social injustice and as a member of Common Goal -- the social impact movement that invests in football projects around the world -- has campaigned for football to put the vast sums of money it generates to good use. In the past he has branded footballers' wages as "obscene," but he is refusing to stop saying things some people may not like.

"I think there are still people that think 'why is this football player speaking about all these things?'" Mata tells ESPN FC in an exclusive interview. "Why not? That's my point of view. Why not? To be honest, it feels like in football, there's still many people only judging by the result or that you only have the right of an opinion if you win. Not necessarily does it have to be like that.

"Raheem, Hector, whoever speaks out, they can have bad days in a game, they can lose games, but they still have these values and they still have the right to speak about what they think. When you don't win or when you don't play good, you receive criticism. And I understand that. And that's fair. But there are still people who think that football players have to stick to their own thing. I don't agree."

Mata has trained in the morning, but instead of putting his feet up at his Cheshire home, he is sat in a side room at United's Carrington training base, still in full kit, discussing ways to make the world a better place.

Thoughtful and engaging, he accepts that as a professional footballer it is his job to score goals, create chances and win games -- particularly at United where the spotlight is as intense as anywhere. But he is also forceful in his opinion that his responsibility extends beyond the training ground and packed stadiums.

"I'm very happy to be a football player." says Mata. "I'm happy to have played many games and win some important trophies. I feel very privileged and lucky about that and hopefully I can win many more. But I think we are here to do, in a way, something else.

"When you're in a profession like this, you have that responsibility in terms of so many people following you, so many people watching the games. I understand that it can be difficult to get out of this routine: the daily routine of training, getting ready because you want to play so you have to train well.

"You give a problem to the manager who has to pick between many players, and then in the game you have to perform because otherwise you're not going to go to the national team. It's all a quite mentally demanding routine to be a professional football player. So to take time to step out of this, and think about all the other things, it might be a challenge, and it is a challenge. But I think if you want, you can do it."

It is two years since Mata became the first footballer to pledge 1% of his salary to Common Goal. Since then, more than 100 other footballers and managers have joined to generate more than $1.5 million.

Mata himself has used time off to visit India and Colombia to see how the money is being used. Premier League clubs alone spent £1.7 billion on transfers during the summer window, of which one 1% would be enough to fund primary and secondary education for 1,815 girls in the Democratic Republic of Congo.

"They're big numbers," says Mata. "It's a reality that there is a lot of money in football. And for me, the problem is not that. That's not a problem at all because football generates a lot of things for the world, and a lot of passion and a lot of money. So it's normal, that something that big generates a lot of money. If we can use a part of that money to actually invest in football, but in a different kind of football, which is a social football, then I think it makes a lot of sense.

"Football generates a lot of money, there's a lot of transfers going around. But at least if we do a percentage of all that money, going directly to football, it is an investment for the future. It's only a part of that big amount of money that is going on in football. That's what we're trying to do. I think it needs to be done. And it will be done because it's right."

With his contract ending on June 30, Mata admits there was a point in the summer when he thought his time at United had come to an end. But, having signed a new deal that could keep him at Old Trafford until he is 34, he is an experienced head in Ole Gunnar Solskjaer's young team and is looking forward to helping his teammates.

Solskjaer has made it clear his aim is to get United back into the Premier League top four and to win a trophy. Having won nine major trophies including the World Cup and the Champions League during a 13-year career, Mata shares the same ambition, but he is not just consumed by goals on the pitch.

"Helping other people is probably more meaningful than scoring a goal in the final," says Mata. "If you can do also something different, a different kind of goal, then much better. I think this is the time now for us as football players, as managers, athletes, to really stand up for our values, to really use the platform that football gives you to.

"I feel that it's only the beginning. I think we are creating something really interesting for football and for society in general."