Sour winner with only a half ticket (6)

I believe the answer is:

acetic

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

'sour winner' is the definition.
'acetic' can be an answer for 'sour' (I've seen this before). I am not certain of the 'winner' bit.

'only a half ticket' is the wordplay.
'only' becomes 'ace' (I am not sure about this - if you are sure you should believe this answer much more).
'a half' indicates taking half.
'ticket' cut in half is 'tic'.
'ace'+'tic'='ACETIC'

'with' is the link.

Can you help me to learn more?

(Other definitions for acetic that I've seen before include "Saucy'" , "Vinegary acid" , "tart" , "sort of acid" , "The acid in vingear" .)

I've seen this clue in the Evening Standard.

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