Stroke trophy containing nothing (4)
I believe the answer is:
coup
'stroke' is the definition.
(I have seen 'Brilliant stroke ' mean 'coup' so perhaps 'stroke' could also mean 'coup')
'trophy containing nothing' is the wordplay.
'trophy' becomes 'cup' (cup is a kind of trophy**).
'containing' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'cup' placed around 'o' is 'COUP'.
(Other definitions for coup that I've seen before include "Brilliant success - seizure of government" , "Sudden success" , "Successful exploit or action" , "Masterstroke" , "rising" .)