Twisted a boy out of a victory (6)
I believe the answer is:
twined
'twisted' is the definition.
(synonyms)
'a boy out of a victory' is the wordplay.
'a boy' becomes 'ted' (short for Edward or Theodore).
'out of' means one lot of letters goes inside another (some letters on the outside of others).
'a victory' becomes 'win' (a win is a victory).
'ted' placed around 'win' is 'TWINED'.
(Other definitions for twined that I've seen before include "Wrapped around or coiled" , "Wound" , "Interlaced" , "Wrapped around like string" .)