Sam Johnstone signs new Manchester United contract until 2018

Manchester United goalkeeper Sam Johnstone has signed a new contract with the club, keeping him at Old Trafford until June 2018 with the option to extend for a further year.

David De Gea and Sergio Romero are United's senior goalkeepers but Johnstone, 23, showed he could feature in Jose Mourinho's future plans when he started in the United manager's first game at the club, a 2-0 preseason win over Wigan Athletic.

Johnstone was part of United's FA Youth Cup-winning side in 2011 -- alongside Paul Pogba and Jesse Lingard -- having been with the club since the age of 10.

"The last 13 years have flown by and I have enjoyed every moment of my time here so far," the Preston-born keeper told United's official website. "I am working with world-class goalkeepers every day and now I am going to use all that experience to push myself and show the manager what I can do."

Although he is yet to play in a competitive game for United, Johnstone has gained experience during several loan spells in the Football League and has represented England under-20s. He was also on United's bench for the opening six games of last season.

"Sam is a goalkeeper with great potential," Mourinho said. "He is a very professional young man with a great attitude to the game. He has progressed immensely even during my short time at the club."