Former Celtic striker Chris Sutton has "great concerns" for Martin O'Neill's side after Rangers "ran all over" them in Sunday's chastening derby defeat. Sutton pinpoints Celtic's "lightweight" midfield as the root of their problems, with Belgium international Arne Engels a glaring loss since his summer exit to West Ham. After being knocked out of the League Cup quarter-finals by their Glasgow rivals, Celtic begin their Europa League camapign at home to Ferencvaros on Thursday before hosting Rangers on Premiership duty three days later.