Solver Sue's beaten us emphatically (9)
I believe the answer is:
ourselves
'us emphatically' is the definition.
(pronoun for referring to one's group with emphasis)
'solver sue's beaten' is the wordplay.
'beaten' is an anagram indicator.
'solver'+'sue'='solversue'
'solversue' with letters rearranged gives 'OURSELVES'.
(Other definitions for ourselves that I've seen before include "We or us personally" , "Us, reflexively" , "Emphatically us" , "See 16" .)