Nick to get off the mark (5)
I believe the answer is:
score
This clue is a double definition.
'nick' is the first definition.
(thesaurus)
'get off the mark' is the second definition.
(to get off the mark is to score a point)
'to' is the link.
(Other definitions for score that I've seen before include "Mark; twenty" , "Hit - music" , "Number of runs" , "Number of goals/points" , "marks" .)