Steps taken to defend strike resulting in shiner (10)
I believe the answer is:
flashlight
'shiner' is the definition.
(I've seen this before)
'steps taken to defend strike' is the wordplay.
'steps' becomes 'flight' (I've seen this before).
'taken' is an insertion indicator.
'to defend strike' becomes 'lash' (I can't justify this - if you can you should believe this answer much more).
'flight' placed around 'lash' is 'FLASHLIGHT'.
'resulting in' is the link.
Can you help me to learn more?
(Other definitions for flashlight that I've seen before include "Electric torch" , "It may be needed to see" , "Beamer" , "One beams brightly" , "shiner" .)