Course’s marker showing skill in smart job (8,4)

I believe the answer is:
starting post
'course's marker' is the definition.
'starting post' can be an answer for 'marker' (I've seen this before). I am not sure about the 'course's' bit.
'skill in smart job' is the wordplay.
'skill' becomes 'art' (both can mean a talent).
'in' indicates putting letters inside.
'smart' becomes 'sting' (both can mean to burn or hurt).
'job' becomes 'post' (post is a kind of job).
'art' put within 'sting' is 'starting'.
'starting'+'post'='STARTING-POST'
'showing' is the link.
Can you help me to learn more?
(Other definitions for starting post that I've seen before include "Marker of course" , "first step in one's career?" , "Marker from which competitors begin race" , "Where race begins" , "Having recently finished training, presumably" .)
