A change of course we hear follows token response to strike (7-6)
I believe the answer is:
'response to strike' is the definition.
(I've seen this before)
'a change of course we hear follows token' is the wordplay.
I cannot really understand how this works, but
'a' is present in the answer.
'change' could be 'counter' (counter is a kind of change) and 'counter' is present in the answer.
'course' could be 'tack' (I've seen this before) and 'tack' is found in the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for counter-attack that I've seen before include "Riposte to an offensive" , "Retaliatory strike" .)