(AP) -- Colby Rasmus' homer started St. Louis' eight-run onslaught against slumping right-hander Bronson Arroyo, and the Cardinals got another solid start from Chris Carpenter for a 10-1 victory over the Cincinnati Reds on Sunday.

Rasmus hit a two-run homer in the first off Arroyo (8-8), who is 1-5 in his last seven starts. A throwing error by third baseman Edwin Encarnacion let in a pair of runs in the fifth inning, helping the Cardinals pull ahead 8-0 with Arroyo on the mound.

Carpenter (6-3) bounced back from his worst start of the season, a 6-3 loss to the Giants on tuesday. The right-hander gave up a run and five hits in seven innings, Fanning Laynce nix on a 94 mph fastball with his 104th and final pitch.

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