Upper hand at court? (9)
I believe the answer is:
advantage
'upper hand' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for advantage that I've seen before include "Benefit, profit" , "Privilege" , "Asset" , "Edge, head start" , "Favourable circumstance" .)