Jon Jay scored from first on right fielder Giancarlo Stanton's throwing error on Shane Robinson's single with two outs in the ninth inning, giving St. Louis a 5-4 victory over the Florida Marlins on Saturday.
Edward Mujica (1-1) worked a scoreless ninth for the Cardinals after Matt Adams' pinch-hit two-run homer tied it two innings earlier.
Jay drew a full-count walk off A.J. Ramos (3-3) with two outs in the ninth and had third easily on Robinson's pinch-hit single.
He then scored without a play after Stanton hesitated before throwing a relay that skipped under Morrison's glove at first base.
The Marlins got homers from Derek Dietrich and Logan Morrison but their run of four straight series wins ended after dropping the first two against the Cardinals.