First in to bat (6)
I believe the answer is:
opener
'first in to bat' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for opener that I've seen before include "Device for accessing contents of tins or bottles" , "Key -- one of two batsman in a side" , "See 1" , "cricketer, first at the crease?" , "Tins need one" .)