Match of rare quality (5)
I believe the answer is:
equal
'match' is the definition.
(synonyms)
'of rare quality' is the wordplay.
'of' indicates a hidden word.
'EQUAL' is hidden within 'rare quality'.
(Other definitions for equal that I've seen before include "Keep pace with - peer" , "The same in quantity, status etc" , "Uniform" , "Like revolting farm animals" , "Peer; evenly balanced" .)