Possible Clues:

• Spy on other half to achieve a sort of victory
• Carefully review a crew member's work?
• Ensure naval officer's ending on board
• Crack team at sea makes decisive act on board
• Ballet at end of play
• Coup for Kasparov
• A Slovak spouse, by the sound of it, puts an end to the game on board
• The winning move in chess
• Final defeat in test match
• Winning chess position