Being the winner, could put cap on him (8)

I believe the answer is:

champion

I'm a little stuck... Click here to teach me more about this clue!

'being' is the definition.
(champion is a kind of being)

'winner could put cap on him' is the wordplay.
'cap on him' can be anagrammed to 'CHAMPION'.
However, I am unsure how this is indicated.

'the' is the link.

Can you help me to learn more?

(Other definitions for champion that I've seen before include "Campaigner or winner" , "One has defeated all others" , "Competitor who has defeated all others" , "Top athlete or victor" , "Overall winner" .)

I've seen this clue in The Irish News.

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