Winners detailed in ancient city (6)

I believe the answer is:

thebes

'ancient city' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for thebes that I've seen before include "place in Greece" , "Greek city of Oedipus" , "Old city of Greece or Egypt" , "Ancient city, a rival to Athens" , "One of the oldest Greek cities" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app