Break early in a race (5)
I believe the answer is:
relay
'race' is the definition.
(relay race)
'break early' is the wordplay.
'break' indicates anagramming the letters.
'early' with letters rearranged gives 'RELAY'.
'in a' is the link.
(Other definitions for relay that I've seen before include "Pass on - put down again" , "Broadcast" , "article in bank" , "Hand, pass on" , "Receive and pass on - race" .)