Hasten to add to the score (3)
I believe the answer is:
run
'hasten' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for run that I've seen before include "A point scored in cricket" , "Move quickly; smuggle" , "Path made by animals" , "A single" , "Manage; function" .)