The block, by Pittsburgh safety Sean Davis, was unnecessary. Steelers linebacker Mark Barron was going to return a fumble for a touchdown without his help. But Davis hit Tyler Lockett in the back, and it was a penalty for illegal block in the back.
Lockett also reacted incredibly with a flop that quite possibly saved the touchdown. It ruled.
The Steelers scored on a 1-yard James Conner touchdown on the ensuing drive. All that hard work, for naught.