Unkempt beard sported by Scotsman from Granite City (10)

I believe the answer is:

aberdonian

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'granite city' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'unkempt beard sported by scotsman' is the wordplay.
'unkempt' indicates an anagram.
'sported by' becomes 'on' (I can't justify this - if you can you should give a lot more credence to this answer).
'scotsman' becomes 'ian' (common Scottish name).
'beard' anagrammed gives 'aberd'.
'aberd'+'on'+'ian'='ABERDONIAN'

'from' is the link.

Can you help me to learn more?

(Other definitions for aberdonian that I've seen before include "person from 20 [GRANITE] city" , "of Scottish city" , "Scottish resident" , "Citizen of Aberdeen" .)

I've seen this clue in The Telegraph.

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