Opener from Sabbath isn't safe, Christian rock (5,5)

I believe the answer is:

saint peter

'christian rock' is the definition.

'opener from sabbath isn't safe' is the wordplay.
'opener from' says to take the initial letters (I've seen 'openers from' mean this (letters which open the words are used)).
'isn't' becomes 'aint' (non-standard version of 'isn't').
'safe' becomes 'peter' (I've seen this in other clues).
The first letter of 'sabbath' is 's'.
's'+'aint'+'peter'='SAINT PETER'

I've seen this clue in The Guardian.

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