Own goal secures victory that's due (5)
I believe the answer is:
owing
'due' is the definition.
('owing' can be similar in meaning to 'due')
'own goal secures victory' is the wordplay.
'own goal' becomes 'og' (football abbreviation).
'secures' indicates putting letters inside.
'victory' becomes 'win' (I've seen this before**).
'og' going around 'win' is 'OWING'.
'that's' acts as a link.
(Other definitions for owing that I've seen before include "Unsettled; on account" , "Outstanding as a debt" , "(Of money) outstanding" , "Undischarged" , "This debt has yet to be paid" .)