Journalist back with drink for important match (7)
I believe the answer is:
decider
'important match' is the definition.
(I've seen this before)
'journalist back with drink' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'back' says the letters should be written backwards.
'with' means one lot of letters go next to another.
'drink' becomes 'cider' (cider is a kind of drink).
'ed' backwards is 'de'.
'de'+'cider'='DECIDER'
'for' acts as a link.
(Other definitions for decider that I've seen before include "Settler" , "Replay perhaps" , "Clinching game" , "It produces a winner after a drawn series" , "Ultimate goal" .)