Wine Soviet intelligence secures with credit (5,3)
I believe the answer is:
grand cru
'wine' is the definition.
(term for high-quality wine)
'soviet intelligence secures with credit' is the wordplay.
'soviet intelligence' becomes 'GRU' (Russian intelligence agency).
'secures' means one lot of letters goes inside another.
'with' becomes 'and'.
'credit' becomes 'cr'.
'and'+'cr'='andcr'
'gru' going around 'andcr' is 'GRAND CRU'.
(Other definitions for grand cru that I've seen before include "fine wine" , "Type of wine" , "A wine of the best grade" , "Superior wine" , "special wine" .)