Way to open excellent sparkling wine (4)
I believe the answer is:
asti
'sparkling wine' is the definition.
(Asti is a type of sparkling wine)
'way to open excellent' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'to open' indicates putting letters inside (some letters open a gap in others).
'excellent' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'st' going into 'ai' is 'ASTI'.
(Other definitions for asti that I've seen before include "Italian town, famous for its wine" , "Alcohol" , "It's a (anag) - wine" , "Italian product" , "Piedmont wine city, SE of Turin" .)