Winning virtuoso is confused about one note (10)
I believe the answer is:
victorious
'winning' is the definition.
(I've seen this before)
'virtuoso is confused about one note' is the wordplay.
'is confused' indicates anagramming the letters.
'about' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'note' becomes 'c' (musical note).
'virtuoso' with letters rearranged gives 'vtorious'.
'i'+'c'='ic'
'vtorious' enclosing 'ic' is 'VICTORIOUS'.
(Other definitions for victorious that I've seen before include "Triumphant" , "winning" .)