Professional player's favourite match (7)
I believe the answer is:
benefit
'professional' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'player's favourite match' is the wordplay.
'player's favourite' becomes 'bene' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'match' becomes 'fit' (synonyms).
'bene'+'fit'='BENEFIT'
Can you help me to learn more?
(Other definitions for benefit that I've seen before include "Fine bet (anag)" , "Advantage or blessing" , "Financial assistance" , "Fine bet on to produce an advantage" , "Handout" .)