Disadvantage defender after indecisive match (8)
I believe the answer is:
drawback
'disadvantage' is the definition.
(drawback is a kind of disadvantage)
'defender after indecisive match' is the wordplay.
'defender' becomes 'back' (left-backs and right-backs are football defenders).
'after' is a charade indicator (letters next to each other).
'indecisive match' becomes 'draw' (I can't explain this - if you can you should give a lot more credence to this answer).
'back' put after 'draw' is 'DRAWBACK'.
Can you help me to learn more?
(Other definitions for drawback that I've seen before include "Disadvantage, problem" , "Fly in the ointment" , "Catch" , "Limitation, disadvantage" , "Hindrance - disadvantage" .)