2011 Atlanta Braves
The Braves had almost no chance of winning the NL East on Sept. 1, but they led the wild card by 8 1/2 games over the Cardinals. Their collapse mirrored that of the Red Sox. Atlanta entered the final night tied with the Cardinals and lost in heartbreaking fashion. Facing the Phillies, stellar Braves closer Craig Kimbrel surrendered the tying run with two outs in the ninth inning. The Phillies went on to win in 13 innings. Earlier, the Cardinals had beaten the Astros 8-0. The Braves' season was over. The Cardinals went an NL-best 18-8 in September. The Braves? 9-18, worst in the NL.