By James Cormack Barcelona take on Osasuna in the second Supercopa de Espana semi-final on Thursday night as they aim to retain their crown. An emphatic victory for the Catalans over Real Madrid in this competition last season set the tone for their eventual La Liga title triumph, although their title defence has so far been a pretty shoddy one. Xavi’s side depart for Saudi Arabia seven points adrift of the current joint leaders. The Catalans take on a middling Osasuna side who qualified for this four-team competition by virtue of their Copa del Rey run last term. Los Rojillos were eventually …