Knocked down as race finished (7)

I believe the answer is:

runover

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'knocked down' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'race finished' is the wordplay.
'race' becomes 'run' (synonyms).
'finished' becomes 'over' (over can mean finished or ended).
'run'+'over'='RUNOVER'

'as' acts as a link.

Can you help me to learn more?

I've seen this clue in The Irish Times.

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