Beaten by exploit, indeed (8)
I believe the answer is:
defeated
'beaten' is the definition.
('defeat' can be a synonym of 'beat')
'exploit indeed' is the wordplay.
I cannot quite see how this works, but
'exploit' could be 'feat' (synonyms) and 'feat' is found within the answer.
The remaining letters 'deed' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'by' is the link.
Can you help me to learn more?
(Other definitions for defeated that I've seen before include "Beat; beaten" , "Thrashed" , "foiled" , "Trounced" , "Whacked" .)