Oddly squad added no depth, losing power for a way to decide the outcome (6,5)

I believe the answer is:

sudden death

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'a way to decide the outcome' is the definition.
I can't tell whether this defines the answer.

'oddly squad added no depth losing power' is the wordplay.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
'no' becomes 'n' (common abbreviation).
'depth' becomes 'd' (abbreviation in geometry).
'losing power' becomes 'eath' (I am not sure about this - if you are sure you should believe this answer much more).
'squad'+'added'='squadadded'
The alternate letters of 'squadadded' are 'sudde'.
'sudde'+'n'+'d'+'eath'='SUDDEN DEATH'

'for' is the link.

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I've seen this clue in The Guardian.

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