 Although already 22, he would spend the next two years registered with its B-team, playing his first season in Tercera División, with promotion.As a versatile defensive unit capable of playing as a right or left back, Cerra found action on either side of the pitch in five La Liga matches, his debut coming on 5 November 2006 in a 1–1 away draw against RCD Espanyol.This was due to a storm of injuries that hit the back-four sector hard in the campaign (Emiliano Moretti and Asier del Horno the more serious ones).