Put name to excellent port (5)
I believe the answer is:
dubai
'port' is the definition.
(UAE port city)
'put name to excellent' is the wordplay.
'put name to' becomes 'dub' (dubbing someone by giving them a name).
'excellent' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'dub'+'ai'='DUBAI'
(Other definitions for dubai that I've seen before include "One of the UAE and its capital" , "Port city on the Persian Gulf" , "sheikdom?" , "capital and port" , "Country" .)