The Kansas City Chiefs managed to win the Super Bowl last season thanks primarily to their high-octane offense, which so often outscored opponents when a young but fast-improving defense had trouble slowing them down. Now it's the defense that is bailing out the offense. While the Chiefs continue to go through what Patrick Mahomes called “growing pains” after Thursday night's 19-8 win over the Broncos, their defense has quietly become one of the best in the NFL.