Upper hand, benefit (9)
I believe the answer is:
advantage
This clue is a double definition.
'upper hand' is the first definition.
(I've seen this in another clue)
'benefit' is the second definition.
(I've seen this before)
(Other definitions for advantage that I've seen before include "First point scored after deuce in tennis" , "Benefit - superior position" , "Favourable circumstance" , "Use" , "Privilege" .)