Crossword Genius

One shot better than the colonel (3)

Ross

I believe the answer is:

par

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'one' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe there's a link between them I don't understand?

I don't understand the remainder of the clue.

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(Other definitions for par that I've seen before include "normal amount" , "Average standard" , "Mean" , "Face value; equal standing" , "level footing" .)

I've seen this clue in the Evening Standard.
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