Defeat with a counter manoeuvre (7)
I believe the answer is:
trounce
'defeat' is the definition.
(synonyms)
'counter manoeuvre' is the wordplay.
'manoeuvre' indicates anagramming the letters.
'counter' is an anagram of 'TROUNCE'.
'with a' is the link.
(Other definitions for trounce that I've seen before include "Beat soundly" , "Massacre" , "Defeat heavily in recount" , "Easily best" , "Defeat heavily (in contest)" .)