Champion drink, beer (9)
I believe the answer is:
supporter
'champion' is the definition.
('supporter' can be a synonym of 'champion')
'drink beer' is the wordplay.
'drink' becomes 'sup' (I've seen this before).
'beer' becomes 'porter' (I've seen this in other clues).
'sup'+'porter'='SUPPORTER'
(Other definitions for supporter that I've seen before include "Strut" , "Second" , "Fan; heraldic figure" , "sports fan?" , "One cheers" .)