Last year the Pittsburgh Steelers were a ridiculously lucky defense. When you look back on the schedule, you see just how fortunate they were in many ways:
No Sam Bradford, instead faced Case Keenum well before he found his footing with Minnesota.
No Aaron Rodgers, instead the defense was barely able to make enough plays to beat Brett Hundley.
Deshaun Watson was injured, and the Steelers beat up on whatever warm body Houston was throwing onto the field that week.
On top of all those, the Steelers were fortunate enough to play the Cleveland Browns twice during their winless season.