Crossword Genius

Stops getting better at cards? (5,2)

Ross

I believe the answer is:

packs up

I'm a little stuck... Click here to teach me more about this clue!

'stops' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'better at cards?' is the wordplay.
'better' becomes 'sup' (I can't explain this - if you can you should give a lot more credence to this answer).
'at' says to put letters next to each other (I've seen this in other clues).
'cards?' becomes 'pack'.
'sup' after 'pack' is 'PACKS UP'.

'getting' is the link.

Can you help me to learn more?

(Other definitions for packs up that I've seen before include "stops working" , "Conks out" , "tidies things away" .)

I've seen this clue in the Evening Standard.
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