the devil's own (something)
1. Very great. (Used primarily before the word "luck.") I can't believe I won the lottery and a radio contest in the same week—I must have the devil's own luck!
2. Very difficult. (Used primarily before the word "job.") I'm having the devil's own job getting this window open—I think its been painted shut.
the devil's own —
a very difficult or great —. informal 1991 Mavis Nicholson Martha Jane & Me It was the devil's own job to get her to give me some money for savings.