Golfer with clubs first to make mistake (7)
I believe the answer is:
clanger
'mistake' is the definition.
(I've seen this before)
'golfer with clubs first' is the wordplay.
'golfer' becomes 'langer' (Bernhard Langer).
'with' says to put letters next to each other.
'first' suggests taking the first letters.
The initial letter of 'clubs' is 'c'.
'langer' put after 'c' is 'CLANGER'.
'to make' acts as a link.
(Other definitions for clanger that I've seen before include "Big blunder" , "Bell possibly" , "boob" , "Bad mistake - loud bell" , "Drop this to make a blunder" .)