A second position brings advantage (5)
I believe the answer is:
asset
'advantage' is the definition.
(I've seen this before)
'a second position' is the wordplay.
'second' becomes 's' (common abbreviation).
'position' becomes 'set' (set is a kind of position).
'a'+'s'+'set'='ASSET'
'brings' acts as a link.
(Other definitions for asset that I've seen before include "Item well worth having" , "virtue" , "Something useful" , "Item conferring advantage" , "Beneficial thing" .)