Manchester United manager Erik ten Hag overruled the board at Manchester United to finalise the £55.3million deal for Lisandro Martinez from Ajax.
The club's scouts had recommended a move for Villarreal's Pau Torres, who has long been a target for the club, but ten Hag persuaded the board to back his pursuit of his former player.
Martinez played under the Dutch manager at Ajax for two seasons, where he was deployed as a centre-back, left-back and centre-midfielder at time.
Whilst signing a central defender this window was not regarded as a priority, with Raphael Varane, Harry Maguire and Victor Lindelof considered adequate cover in that position, Martinez becomes the Red Devils' third signing of the summer.