Starting in 1947, the NFL teams played a 12 game schedule rather than 11 games. The twelfth game proved to be crucial for the Steelers, Eagles, Cardinals and Bears. In the Eastern Division, Pittsburgh took a half-game lead over Philadelphia after a 35–24 win in Week Five. On November 30, the Eagles won the rematch, 21–0, to take a 7–3–0 to 7–4–0 lead. The same day, the Cardinals lost to the Giants, 35–31, while the Bears beat Detroit 34–14; the 7–3–0 Cards were a game behind the 8–2–0 Bears in the Western Division.
In Week Twelve, the Cardinals beat the Eagles, 45–21. Pittsburgh beat Boston 17–7, while the Bears lost to the Rams, 17–14. The result was that the Steelers finished at 8–4, and the 7–4 Eagles had to win their last game. The Cardinals and Bears were both at 8–3, and the Western title would go to the winner of their December 14 season-closer. A crowd of 48,632 turned out at Wrigley Field to watch. The Cardinals won the game, 30–21, and the right to host the championship. The same day, Philadelphia beat Green Bay, 28–14, to force a playoff with Pittsburgh.