Brandon Moss bounced out of a three-week skid with a tiebreaking home run and Aledmys Diaz connected in his return to the starting lineup, leading the Cardinals to a 4-2 win over the Chicago Cubs on Tuesday night.
St. Louis ensured that the runaway Cubs won't clinch the NL Central at Busch Stadium. Chicago's magic number is three, and the series wraps up Wednesday.
The Cardinals remained a half-game behind the New York Mets for the second wild-card spot.
Moss entered the game mired in a 1-for-41 skid.
Moss slammed a two-run homer in the sixth off Jason Hammel (14-9).
The Cubs' Dexter Fowler led off the game with a home run against Jaime Garcia.
Alex Reyes (2-1) won with 4 1/3 innings of scoreless relief. Kevin Siegrist got his second save.
Hammel allowed four runs on six hits in 5 2/3 innings. He struck out nine and walked two.
Jon Lester (16-4, 2.51) takes on RHP Carlos Martinez (14-7, 3.05) in the final game of the three-game set. Lester has allowed fewer than two runs in each of his last five starts. He is 6-0 with a 1.17 ERA in his previous eight starts. Martinez is 6-3 in 11 day starts this season. He has induced an NL-leading 32 double plays.