Clear identification needed to enter race (7)
I believe the answer is:
evident
'clear' is the definition.
('evident' can be a synonym of 'clear')
'identification needed to enter race' is the wordplay.
'identification' becomes 'id'.
'needed to enter' is an insertion indicator.
'race' becomes 'event' (I've seen this before).
'id' inserted into 'event' is 'EVIDENT'.
(Other definitions for evident that I've seen before include "Quite obvious, easy to see" , "'Plain, apparent (7)'" , "Clearly apparent" , "on display" , "Quite obvious and clear" .)