Riddle wasn’t originally supposed to win the United States title
Keith Lee was supposed to be in the United States Title match and win the title, but he was pulled due to health issues. The company needed a triple threat match situation because Bobby Lashley couldn’t take a pinfall to drop the title. He was already in line to become WWE Champion and couldn’t suffer a loss.
Since Lee was pulled from the match, John Morrison won a multi-man match during the kickoff show to get into that United States Title match and he took the pinfall.