Chris Johnson homered in the eighth and ninth innings Tuesday night, giving him five in eight games since being acquired in a trade, to rally the Arizona Diamondbacks to a 10-4 victory over the Pittsburgh Pirates. Johnson's homer in the eighth carried far over the fence in center field and capped a four-run rally against Jason Grilli (1-4) that put Arizona ahead 7-4. Pittsburgh had just taken a 4-3 lead with two runs in the seventh. 