Attack group winning over knight (3,4)
I believe the answer is:
set upon
'attack' is the definition.
(I know that set upon is a more specific form of the action attack)
'group winning over knight' is the wordplay.
I cannot quite see how this works, but
'group' could be 'set' (both can mean a collection) and 'set' is present in the answer.
'winning' could be 'up' (eg being up at half time in football) and 'up' is located in the answer.
'over' could be 'on' (physically on top of) and 'on' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for set upon that I've seen before include "Attacked" , "Attack" , "Determined to do (something)" , "Mug" .)