Related Clues:

• Down Under pal
• Bosun's ___
• King's downfall, maybe
• Final check
• 9-Across ending
• Captain's subordinate
• Best on a chessboard
• Missing sock
• Other half
• Other sock, say
• Play or room follower
• Fischer coup de grace
• The killer move in chess
• Winning call on board
• Team up with partner