Competitors before match experiment in practice (5,4)

I believe the answer is:

field-test

'experiment in practice' is the definition.

'competitors before match' is the wordplay.
'competitors' becomes 'field' (term for those fielded in a competition).
'before' is a charade indicator (letters next to each other).
'match' becomes 'test' (test match is a kind of match**).
'field'+'test'='FIELD-TEST'

(Another definition for field-test that I've seen is " Left diets (anag.); scientific trial".)

I've seen this clue in The Guardian.

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