It was the earliest any team in National League history clinched a pennant, but that record comes with a big asterisk. The nation was fighting in World War I. The government announced that September 2nd was the last day for anyone who was of draft age to report for duty, or to find a war related job. This included the ballplayers themselves—although a waiver was granted for anyone playing in the World Series. Baseball wasn’t considered essential.
The Cubs faced Babe Ruth and the Red Sox in that World Series, and lost it in 6 games. The Red Sox wouldn't win another World Series for 86 years.
