Defender was hard, leading to repercussion (8)
I believe the answer is:
backwash
'to repercussion' is the definition.
(thesaurus)
'defender was hard leading' is the wordplay.
'defender' becomes 'back' (I've seen this before).
'leading' indicates taking the first letters.
The initial letter of 'hard' is 'h'.
'back'+'was'+'h'='BACKWASH'
(Other definitions for backwash that I've seen before include "Unpleasant after-effects" , "Wake" .)