Pryor's score was the longest touchdown run by a quarterback in NFL history and set the Raiders on their way to a 21-18 victory over the Steelers.
The 24-year-old, who also became just the fourth quarterback since 1970 to have multiple 100-yard rushing games in a season, admitted his surprise at seeing the field so open, but believes that the score was a result of his team's game plan.
"I was very surprised, because it's never open like that. Very surprised. But with the game plan, the way they put things together, it doesn't surprise me that sometimes it may happen like that," Pryor told the Associated Press.
Despite the win, the Raiders are still bottom of the AFC West ahead of next Sunday's match against the Philadelphia Eagles.