The Cardinals took two of three from NL Central-leading Milwaukee and pulled within one game of the division lead.
Lackey (1-0) was the Cardinals' big catch at the trade deadline that capitalized on Boston's sell-off. The right-hander won the clinching Game 6 of the World Series against St. Louis last fall allowed two runs and seven hits in seven innings and is 12-7 overall.
Trevor Rosenthal struck out Carlos Gomez with two on for his major league-leading 34th save in 38 chances.
Milwaukee starter Matt Garza was pulled after allowing one hit in six innings.
Matt Holliday homered off Zach Duke with one out in the seventh. Recently acquired A.J. Pierzynski hit a tying single off Jeremy Jeffress (0-1) and Taveras singled up the middle.
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