Roman has drink with Greek in perfect setting (8)
I believe the answer is:
agricola
'roman' is the definition.
(Roman general)
'greek in perfect setting' is the wordplay.
'greek' becomes 'gr'.
'in' is an insertion indicator.
'perfect' becomes 'ai' (I've seen this in other clues).
'setting' becomes 'cola' (I am not sure about this - if you are sure you should believe this answer much more).
'gr' placed inside 'ai' is 'agri'.
'agri'+'cola'='AGRICOLA'
'has drink with' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
(Other definitions for agricola that I've seen before include "Ancient soldier" , "Roman general who conquered much of Britain" , "Old general" .)