When the Cubs play St. Louis it's like the World Series to them. They really get up for those games, and have beaten them in the season series last year and this year with an inferior team.
The Reds beat them like a step child. 3 more games with the Cubs, and the Cards have 6 more with them. Consevatively speaking, that should equate to +3 games for the Reds. Those 3 games will come in handy later on!