In the late 1930s, Halas—with University of Chicago coach Clark Shaughnessy—perfected the T-formation system to create a revolutionary and overwhelming style of play which drove the Bears to an astonishing 73–0 victory over the Washington Redskins in the 1940 NFL Championship Game—still the most lopsided margin of victory in NFL history. Every other team in the league immediately began trying to imitate the format. The Bears repeated as NFL champions in 1941, and the 1940s would be remembered as the era of the "Monsters of the Midway".