Be defeated as doctor won dog (2,4)
I believe the answer is:
go down
'dog' is the definition.
The definition and answer can be both to do with motion as well as being verbs in their base form.
Perhaps there's an association between them I don't understand?
'be defeated as doctor won' is the wordplay.
I cannot really see how this works, but
'be' could be 'go' (going is a kind of being) and 'go' is found in the answer.
'doctor' could be 'd' (eg in PhD, Doctor of Philosophy) and 'd' is found in the answer.
an anagram of 'won' is 'own' which is within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for go down that I've seen before include "leave university" , "spiritual command to Moses" , "Be recorded" , "Fall" , "Descend - be relegated" .)