Sign up now! Sign up now! Sign up now? Sign up now! When Celtic opened the scoring against Lask courtesy of a low Callum McGregor shot after 21 minutes on Tuesday night, the Scottish champions looked to have exorcised their Bigger Cup demons from 12 months ago. Four goals ahead of their Austrian hosts on aggregate, it seemed utterly inconceivable that Martin O’Neill’s side could emulate, let alone eclipse, their humiliation at the hands of Kairat Almaty last August and the match commentator int…