Accredited goal secures championship (8)
I believe the answer is:
entitled
'accredited' is the definition.
'goal secures championship' is the wordplay.
'goal' becomes 'end' (both can mean a purpose).
'secures' is an insertion indicator.
'championship' becomes 'title' (a championship is a sporting title).
'end' placed around 'title' is 'ENTITLED'.
(Other definitions for entitled that I've seen before include "Given right - named" , "with style" , "Named; allowed" , "Authorised; bearing the name" , "Gave a right to, or named a book" .)