Back 1981 National winner (8)
I believe the answer is:
champion
'winner' is the definition.
(I know that winner can be written as champion)
'back 1981 national' is the wordplay.
I cannot really see how this works, but
'national' could be 'am' and 'am' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for champion that I've seen before include "gain position on top" , "Person who has defeated all others in a competition" , "Support - victor" , "Tournament winner" , "Champ" .)