A reduction on top is clearly superior (1,3,5)
I believe the answer is:
a cut above
'clearly superior' is the definition.
'a reduction on top' is the wordplay.
'reduction' becomes 'cut' (cut is a kind of reduction).
'on top' becomes 'above'.
'a'+'cut'+'above'='A CUT ABOVE'
'is' is the link.
(Other definitions for a cut above that I've seen before include "Something superior" , "Noticeably superior to" .)