Jason Heyward singled three times with an RBI, and Peter Bourjos hit a run-scoring triple for the NL Central leaders, who took three of four from the second-place Cubs.
Lackey had been 6 for 67 at the plate in 13 major league seasons before a two-out, opposite-field RBI double to right in the fourth. Bourjos, who had been on first base, scored for a 4-0 lead on an error by Jorge Soler who, with his back to the plate, missed the ball as he tried to glove it between his legs near the foul line.