Possible Clues:

• This will sound finally with the final winner in hand
• Bridge players' call to judgement?
• Ultimate demagogue that will usher in day of reckoning
• Final card for final blow
• The final winner on the Day of Judgement?
• It's on the cards there may be no more winners after this; that's the final blow
• That's the final card for the Day of Judgement
• Is that the final winner on Judgment Day, by the sound of it?
• Have the final winner in hand before judgment, by the sound of it
• The final card of its kind may be 33 across on the Day of Judgement