In 2016, the Cubs took over
After over-achieving in 2015, the Cubs knew their true time to win was in 2016. Even with Kyle Schwarber lost to a knee injury for much of the season, the Cubs would enjoy one of their best seasons in franchise history.
Behind strong performances from Jon Lester (19-5, 2.44 ERA), Kyle Hendricks (16-8, 2.13 ERA) and Jake Arrieta (18-8, 3.10 ERA), the Cubs won 103 games and bested the Cardinals by 17.5 games.
Despite winning over 100 games, the Cubs and Cardinals played each other fairly even last season. In 19 games between the two rivals, the Cubs won 10, while outscoring the Cardinals 91-70.
With the Cubs firmly in control of the division for the majority of the 2016 season, the Cardinals were forced to assume the role of chasers like the Cubs had for so many years. While the Cardinals did not finish in last place in the division last season, that was partly due to the poor play of the other three teams in the division. The Cubs and Cardinals won 103 and 86 games respectively in 2016. In addition to that, the Pirates won just 78 while the Brewers won 73 and the Reds finished with less than 70 victories.