Cricketing pair seen outside harbour town and city (6)
I believe the answer is:
oporto
'city' is the definition.
(I've seen this before)
'cricketing pair seen outside harbour' is the wordplay.
'cricketing pair' becomes 'oo' (I can't explain this - if you can you should give a lot more credence to this answer).
'seen outside' is an insertion indicator.
'harbour' becomes 'port' (I've seen this before).
'oo' going around 'port' is 'OPORTO'.
'town and' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for oporto that I've seen before include "Iberian city" , "Second largest city in Portugal" , "Iberian location" , "European city" , "City near the mouth of the River Douro" .)