Delivery for one unable to rise before ten! (5,2,3,4)
I believe the answer is:
saved by the bell
'delivery' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'one unable to rise before ten' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'the' (both can introduce a definite example of something) and 'the' is found within the answer.
'before' could be 'by' and 'by' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for saved by the bell that I've seen before include "mice hoped to be" , "Relieved by timely intervention" , "Fighter may be" .)