Key match has editor turning to drink (7)
I believe the answer is:
decider
'key match' is the definition.
'decider' can be an answer for 'match' (I have seen 'Important match' mean 'decider' so perhaps 'match' could also mean 'decider'). I am unsure of the 'key' bit.
'editor turning to drink' is the wordplay.
'editor' becomes 'ed' (abbreviation).
'turning' shows that the letters should be reversed in order.
'to drink' becomes 'cider' (alcoholic drink).
'ed' in reverse letter order is 'de'.
'de'+'cider'='DECIDER'
'has' acts as a link.
Can you help me to learn more?
(Other definitions for decider that I've seen before include "It settles the matter" , "Crucial final game" , "vital match" , ""Golden goal", for example" , "The game that determines the series winner" .)