Related Clues:

• Sabin development
• Right or left
• Front end of a one-two
• Medical breakthrough
• The 'one' in a one-two
• Uppercut set-up
• Ring leader?
• Smart remark
• Abrupt thrust
• Friendly poke
• Boxer's weapon
• The 'one' of a one-two
• Start of a one-two punch
• Quick hit
• Poke