Film is about victory celebration (5)
I believe the answer is:
revel
'celebration' is the definition.
(revel is a kind of celebration)
'film is about victory' is the wordplay.
'film' becomes 'reel' (reel is a kind of film).
'is about' is an insertion indicator.
'victory' becomes 'v'.
'reel' placed around 'v' is 'REVEL'.
(Other definitions for revel that I've seen before include "Make merry; luxuriate (in)" , "Be festive, enjoy" , "Take great delight (in)" , "Feast riotously" , "Make merry, have a ball" .)