Popular win away from sea (6)
I believe the answer is:
inland
'away from sea' is the definition.
'popular win' is the wordplay.
'popular' becomes 'in'.
'win' becomes 'land' (both can mean to secure or obtain**).
'in'+'land'='INLAND'
(Other definitions for inland that I've seen before include "Away from the sea" , "from the seaside" , "Remote from the sea" , "Situated away from the coast" , "towards a country's interior" .)