Jordy Mercer’s first career grand slam pushed the Pirates to the brink of something even rarer: A series win at Miller Park. Mercer’s slam off Matt Garza capped a five-run sixth. Top Milwaukee prospect Orlando Arcia answered with a three-run shot in the bottom of the inning — his first career home run — but the Pirates held on, 5-3, to remain 2 1/2 games back of the second National League Wild Card.