Crossword Genius

One, a devil in disguise, helped (7)

Ross

I believe the answer is:

availed

'helped' is the definition.
(availing is a kind of helping)

'one a devil in disguise' is the wordplay.
'one' becomes 'a'.
'in disguise' indicates anagramming the letters.
'a'+'devil'='adevil'
'adevil' with letters rearranged gives 'vailed'.
'a'+'vailed'='AVAILED'

(Other definitions for availed that I've seen before include "Used, put into service" , "Profited from" , "Helped" , "Used to one's advantage" .)

I've seen this clue in the Sydney Morning Herald.
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