Confirm minister who finally fixed drain (6)

I believe the answer is:

ordain

I'm a little stuck... Click here to teach me more about this clue!

'confirm minister' is the definition.
I can't judge whether this defines the answer.

'who finally fixed drain' is the wordplay.
'finally' suggests the final letters.
'fixed' indicates an anagram.
The final letter of 'who' is 'o'.
'drain' is an anagram of 'rdain'.
'o'+'rdain'='ORDAIN'

Can you help me to learn more?

(Other definitions for ordain that I've seen before include "Inroad (anag.)" , "Initiate as priest" , "Appoint as priest" , "Install as priest" , "Consecrate as priest" .)

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

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