Appearing as card game champion (7)
I believe the answer is:
looking
'appearing' is the definition.
('look' can be a synonym of 'appear')
'card game champion' is the wordplay.
'card game' becomes 'loo' (historic card game found in Jane Austen novels).
'champion' becomes 'king' (I've seen this in other clues).
'loo'+'king'='LOOKING'
'as' is the link.
(Other definitions for looking that I've seen before include "Viewing" , "Seeming to be; gazing" , "Seeming, appearing" , "Watching" , "Appearing (like)" .)