Club Atlético Vélez Sarsfield
Born in Buenos Aires, Pacheco started playing with Club Atlético Vélez Sarsfield, but moved with his parents to Spain still in his teens, where he finished his formation with Atlético Madrid. In the 2009–10 season he had his first taste of professional football, being loaned to neighbouring Rayo Vallecano in the second division; however, the loan was short-lived, as he returned in January 2010 to the "Colchoneros", spending the following months with its reserves in the third level.