Victor’s a champion! (6)
I believe the answer is:
winner
I believe this clue is a double definition.
'victor's' is the first definition.
('winner' can be a synonym of 'victor')
'a champion' is the second definition.
(thesaurus)
(Other definitions for winner that I've seen before include "film director" , "success" , "One that came first" , "Top player" , "One succeeds" .)