Perfect decider at Wembley netted close to time (6)
I believe the answer is:
refine
'perfect' is the definition.
(I've seen this in another clue)
'decider at wembley netted close to time' is the wordplay.
I cannot quite see how this works, but
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for refine that I've seen before include "Purify or make more cultured" , "Purify or improve" , "Make pure" , "Hone" , "Remove impurities as from oil" .)