Working alone (6-6)
I believe the answer is:
single-handed
'working alone' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for single-handed that I've seen before include "Working alone" , "Unaided" , "Unassisted" , "Done without help from others" , "Glen dashed in (anag) -- entirely alone" .)