Wacha (3-0) allowed two hits, walked two and struck out two in the 97-pitch effort. He added a two-run single at the plate for the Cards, who with a three-game sweep moved 1 1/2 games ahead of the second-place Pirates in the National League Central.
Pittsburgh's Charlie Morton (7-4) coughed up five runs and six hits before leaving in the second inning with a foot injury.
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