Virtually unique service and comfort ... (6)
I believe the answer is:
solace
'comfort' is the definition.
('solace' can be a synonym of 'comfort')
'virtually unique service' is the wordplay.
'virtually' means to remove the last letter (all but the last letter).
'unique' becomes 'sole' ('sole' can be a synonym of 'unique').
'service' becomes 'ace' (ace is a kind of service).
'sole' with its last letter taken off is 'sol'.
'sol'+'ace'='SOLACE'
'and' acts as a link.
(Other definitions for solace that I've seen before include "Comfort in time of disappointment or sorrow" , "Something that comforts distress" , "Kind of comfort - a close thing" , "Comport" , "Consolation, comfort" .)