Endures final on Sunday (5)
I believe the answer is:
lasts
'endures' is the definition.
('last' can be a synonym of 'endure')
'final on sunday' is the wordplay.
'final' becomes 'last' (synonyms).
'on' is a charade indicator (letters next to each other).
'sunday' becomes 's'.
'last'+'s'='LASTS'
(Other definitions for lasts that I've seen before include "Keeps on" , "Goes on" , "carries on" , "Endures" , "Holds out" .)