Very close races -- if so, phone this criminal (5,8)

I believe the answer is:

photo finishes

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'very close races' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'if so phone this criminal' is the wordplay.
'criminal' indicates an anagram.
'if'+'so'+'phone'+'this'='ifsophonethis'
'ifsophonethis' anagrammed gives 'PHOTO FINISHES'.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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