Ireland seal nervy win over Argentina but Sean O’Brien a casualty

• Ireland 28-17 Argentina• Kieran Marmion also taken off injured before All Blacks clashIreland laboured to a patchy 28-17 victory over Argentina in Dublin, losing Sean O’Brien and Kieran Marmion to serious-looking injuries.Marmion, Bundee Aki and Luke McGrath scored Ireland’s tries as the Six Nations champions started their November campaign with a staccato win over the stubborn Pumas. Bautista Delguy crossed for Argentina, who edged ahead in the second-half through Nicolás Sánchez’s third penalty before Ireland battled back as Johnny Sexton finished with 13 points . Related: Wales break losi…