Key or corkscrew (6)
I believe the answer is:
opener
I believe this is a double definition.
'key' is the first definition.
(I've seen this before)
'corkscrew' is the second definition.
(I've seen this in another clue)
(Other definitions for opener that I've seen before include "First part" , "(Team's) first batsman" , "It may provide access to food" , "batsman facing new ball" , "Tins need one" .)