Drained of strength, welcomed credit and fought (8)
I believe the answer is:
scrapped
'fought' is the definition.
(I've seen this before)
'drained of strength welcomed credit' is the wordplay.
'drained of strength' becomes 'sapped' (I've seen this before).
'welcomed' indicates putting letters inside (in sense of 'invited in').
'credit' becomes 'cr'.
'sapped' enclosing 'cr' is 'SCRAPPED'.
'and' is the link.
(Other definitions for scrapped that I've seen before include "did battle" , "Cancelled; fought" , "Disposed of something useless" , "Disposed of or had a fight" , "Fought - ceased to use" .)