Race is run through small wood (6)
I believe the answer is:
streak
'race' is the definition.
(I've seen this before)
'run through small wood' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'through' indicates putting letters inside (inserted letters go through the word).
'small' becomes 's' (abbreviation - e.g. clothes size).
'wood' becomes 'teak' (type of timber).
's'+'teak'='steak'
'r' placed inside 'steak' is 'STREAK'.
'is' acts as a link.
(Other definitions for streak that I've seen before include "Irregular contrasting stripe" , "Unbroken series, of luck say" , "Dash (in the nude?)" , "Run of luck" , "Strip of a different colour" .)