Manchester United have confirmed they have triggered a one-year extension clause in Juan Mata's contract that will keep him at Old Trafford until 2019.

The Spain international joined the Red Devils from Chelsea for a then club-record fee of £37.1m ($52.7m) in January 2014. United manager Jose Mourinho was in charge at Stamford Bridge when he sanctioned Mata's sale to the 20-time champions of England four years ago.

Mata had six months left on his earlier contract and United have now extended his stay by triggering a clause that will see him extend his stay at Old Trafford by one more season.

"Manchester United have triggered a clause to extend Juan Mata's contract by one year, tying the Spaniard to the club until June 2019," a statement read on United's official website.

When Mourinho arrived at United in 2016, there were reports suggesting the Portuguese tactician would offload Mata. However, the former Valencia star has become one of the key players for the Red Devils manager.

Mata has scored three goals and registered three assists in 19 Premier League appearances this season. Mourinho explained the Spaniard is an "important player for the club", which has seen him continue his stay with his current employers.

"Mata is very important. When I arrived one-and-a-half years ago, [they said], 'Mata is in trouble, in trouble, in trouble', and now he's getting an extension of one more year. An important player for me; important player for the club; important player for the other players," Mourinho told United's official website.

The player, who expressed his delight, stressed that he is privileged to continue at United.

"I still feel very happy and very proud to be part of this club. I think everyone that belongs to Manchester United should feel privileged, and that's how I feel," Mata explained.

"I'm happy with everyone at the club and, obviously, with the manager and my team-mates. Once you are part of this club, your football career is not the same; it changes, because this is one of the biggest clubs in football history.

"Every day I try to tell myself how lucky and how privileged I am, try to take advantage of every single training session, and try to see how important it is to be a Manchester United player."

Mata, who is reportedly earning £140,000-a-week at Old Trafford has pledged to donate 1% of his salary to charity and has seen several top flight footballers across the globe join the cause.

Juan Mata
Juan Mata arrived at Manchester United from Chelsea in January 2014 Reuters