Record set by American in field event (6)
I believe the answer is:
discus
'field event' is the definition.
(discus is a kind of field event)
'record set by american' is the wordplay.
'record' becomes 'disc' (eg a CD, compact disc).
'set by' says to put letters next to each other.
'american' becomes 'us' (abbreviation for United States).
'disc'+'us'='DISCUS'
'in' acts as a link.
(Other definitions for discus that I've seen before include "Field event projectile" , "Circular object thrown in sports" , "flat missile" , "Athlete's projectile" , "Sporting missile" .)