Advance warning re Chief Superintendent's three top picks (5-2)

I believe the answer is:

heads-up

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

'advance warning' is the definition.
(I've seen this in another clue)

're chief superintendent's three top picks' is the wordplay.
I cannot really understand how this works, but
'chief' could be 'head' (synonyms) and 'head' is present in the answer.
The remaining letters 'sup' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...

Can you help me to learn more?

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

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