Service from graduate isn't fantastic (6)
I believe the answer is:
Here is my best explanation:
'service' is the definition.
'graduate isn't fantastic' is the subsidiary indication.
'graduate' becomes 'ma' (**).
'fantastic' indicates anagramming the letters.
'isnt' with letters rearranged gives 'tins'.
'from' is the link.
(Other definitions for matins that I've seen before include "Isn't ma given to morning prayers?", "Morning prayers or bird-songs", "Church service", "Anglican morning service", "Morning service" and "C of E's daily morning service".)