The point in running is to win (4)
I believe the answer is:
gist
'the point' is the definition.
(thesaurus)
'in running is to win' is the wordplay.
'in' indicates the answer is hidden within the clue.
'GIST' is hidden within 'running is to win'.
(Other definitions for gist that I've seen before include "Main idea, kernel of matter" , "Substance or general idea" , "Essential point or general sense of anything" , "Meat" , "Real point or substance" .)