Brilliant solving (8)
I believe the answer is:
cracking
This clue is a double definition.
'brilliant' is the first definition.
(cracking can be slang term for amazing)
'solving' is the second definition.
(e.g. cracking a code)
(Other definitions for cracking that I've seen before include "Solving" , "great!" , "Wonderful" , "failing" , "very fast" .)