Very good one (3)

I believe the answer is:
ace
I believe this is a double definition.
'very good' is the first definition.
(I've seen this before)
'one' is the second definition.
(ace has a value of one in some card games)
(Other definitions for ace that I've seen before include "Top card or winning tennis serve" , "Card with a single pip" , "Playing card with a single symbol" , "Crack" , "Expert (sl.)" .)