Admit having won wrongly (3)
I believe the answer is:
own
'admit' is the definition.
(own can mean to admit or acknowledge)
'won wrongly' is the wordplay.
'wrongly' indicates anagramming the letters.
'won' with letters rearranged gives 'OWN'.
'having' acts as a link.
(Other definitions for own that I've seen before include "Private" , "Posses" , "Possess - recognise - admit" , "Allow" , "Personal; possess" .)