The Cubs may soon come to regret giving this rival's postseason hopes new life

In their four-game sweep at the hands of the Cincinnati Reds at Great American Ballpark this past weekend, the Chicago Cubs not only failed to solidify their hold on the first wild card spot, but they also violated one of the cardinal rules of competition. When you have a chance to finish off a fellow contender, you must do so.

The losses meant that the San Diego Padres, who entered the weekend five games behind the Cubs, now trail by only 2 1/2 games with six remaining after punching their postseason ticket with a walk-off win on Monday. San Diego finishes with home series against the Brewers and Arizona Diamondbacks – who are also battling for playoff consideration – so making up those three games won’t be easy.

But it sounds more doable than making up five games.

Cubs have opened the door for the Reds to sneak into the postseason

From a standpoint of karma, the larger problem is that the Cubs gave life to the previously moribund Reds. Cincinnati entered the series two games behind the New York Mets in the fight for the final wild card spot. Now the Reds are in that final wild card spot, which means they are a potential October rival for the Cubs.

And given that Reds pitchers held the Cubs to just seven runs in four games with two 1-0 shutouts, I think we know which pitching staff the Cubs do not want to see down the road.

Teams that fail to take advantage of a final-week chance to polish off a potential postseason rival can live to regret that failure. Just last season, the Milwaukee Brewers, already long enshrined as NL Central champions, took the field on the final day of the regular season with a chance to cancel the playoff hopes of the New York Mets.

All the Brewers needed was a Sunday win to send the Mets home and the Atlanta Braves and Arizona Diamondbacks into the postseason. Instead the hungrier Mets beat the self-satisfied Brewers 5-0, positioning themselves to split a Monday makeup doubleheader with the Braves that gave both of those teams postseason access.

In that postseason, the Mets made the Brewers regret their failure to drive the dagger home when they had the chance on that final Sunday. The Mets took out the Brewers in a three-game Wild Card Series in Milwaukee before being eliminated by the Dodgers in the NLCS.

One week earlier, the Mets had hosted the soon-to-be division champion Phillies in a similar circumstance. The Phillies had all but formally clinched the NL East, the Mets needed every win. New York won three games of the four-game series to stay in post-season contention.

Two weeks later, the Mets and Phillies met again, this time in the division series round. The Mets again won three games to one, eliminating the defending NL champs. Had the Phillies taken care of business two weeks earlier, New York never would have gotten that chance.

On a grander scale, Cubs fans are quite familiar with the principle that you eliminate potential threats when you can. Four games into the 2016 World Series, the Cleveland Indians had the Cubs at the brink of the cliff, leading three games to one. But the Indians failed to close the deal in games five or six, and you know the rest.

There is a bit of irony in the fact that the Cubs, having failed to eliminate the Reds this past weekend, are now in position to sanctify them. While the Reds are taking on their cousins from Pittsburgh, the Cubs host the Mets, precisely the team the Reds now need to hold off for that final wild card spot. So it appears very much like the Cubs will decide which team wins that spot.

 One only hopes that whichever team emerges, they don’t make the Cubs rue their failure to eliminate that team when they had a chance.