Record making competitor (5)
I believe the answer is:
entry
I believe this is a double definition.
'record' is the first definition.
(eg entry in a list)
'competitor' is the second definition.
(entry in a competition)
'making' acts as a link.
(Other definitions for entry that I've seen before include "Admission" , "Gate" , "vestibule" , "Item in an account book" , "One in competition" .)