I win — diagram has parts missing (5)
I believe the answer is:
india
'i' is the definition.
(India is I in the NATO phonetic alphabet)
'win diagram has parts missing' is the wordplay.
'has parts missing' indicates the answer is hidden within the clue.
'INDIA' is hidden within 'win diagram'.
(Other definitions for india that I've seen before include "Commonwealth state" , "Country of the Ganges" , "Cricket team" , "Eastern country" , "Country of Gandhi" .)