Paul Goldschmidt and Nolan Arenado combined for six hits and the Cardinals roughed up Luis Castillo for six runs in the first inning to beat the Cincinnati Reds 11-6 Thursday.
Dylan Carlson hit a three-run homer and Tyler O'Neill connected for a two-run shot.
St. Louis starter Jack Flaherty couldn't take advantage of the big lead, giving up six runs in 4 1/3 innings. Giovanny Gallegos (1-0), the fourth of five Cardinals relievers, got the win.
Castillo (0-1) had a bad day almost from the start. He surrendered 10 runs, eight of them earned, on eight hits over 3 1/3 innings.
Goldschmidt, who had four hits and scored three times, doubled with one out in the first and Arenado, the star third baseman acquired in an offseason trade from Colorado, followed with a single.
An error by shortstop Eugenio Suarez, who was moved over from third base in spring training, let two runs score and Carlson homered to cap the burst.
Singles by Goldschmidt and Arenado and another error by Suarez led to another run in the second.
The Cardinals added four more in the fourth on an RBI single by Goldschmidt, a wild pitch and O'Neill's drive.
Suarez homered in the bottom of the fourth. Nick Castellanos homered, doubled and singled for the Reds, who chipped away but couldn't score runs in bunches.
Down 11-6 in the sixth, they loaded the bases with one out. But Castellanos' liner to center fielder was snagged by Carlson, who doubled off Tyler Stephenson at second base.