Old city has time for top quality (3,4)
I believe the answer is:
the best
'top quality' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'old city has time' is the wordplay.
'old city' becomes 'Thebes' (ancient Greek city).
'has' means one lot of letters go next to another.
'time' becomes 't' (abbreviation).
'thebes'+'t'='THE BEST'
'for' is the link.
Can you help me to learn more?
(Another definition for the best that I've seen is " second to none".)