The stage set for defender to fall (8)
I believe the answer is:
backdrop
'the stage set' is the definition.
(backdrop is a kind of stage set)
'defender to fall' is the wordplay.
'defender' becomes 'back' (I've seen this in other clues).
'to fall' becomes 'drop' (dropping is a kind of falling).
'back'+'drop'='BACKDROP'
'for' is the link.
(Other definitions for backdrop that I've seen before include "Scenery hung at the rear of a stage" , "Wider view" , "Against which action is played out" , "Setting for a scene" , "Painted curtain at rear of stage" .)