Winning fellow in duel chose to turn early (5,2,8)

'early' is the definition.
(I've seen this in another clue)

'winning fellow in duel chose to turn' is the wordplay.
I cannot really see how this works, but
'winning' could be 'ahead' (both can mean in the lead) and 'ahead' is located in the answer.
'fellow' could be 'he' ('he' refers to a man) and 'he' is found in the answer.
an anagram of 'duel' is 'dule' which is within the answer.
This may be the basis of the clue (or it may be nonsense).