In the next race for a run (5)
I believe the answer is:
extra
'a run' is the definition.
(cricket run)
'in the next race for' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EXTRA' is hidden in the letters of 'next race for'.
(Other definitions for extra that I've seen before include "Bit part actor" , "leg bye perhaps" , "Additional - run - actor - newspaper edition" , "more than usually" , "Bonus; surplus" .)