Zack Greinke and Madison Bumgarner both pitched well in a showdown of NL West aces, but Welington Castillo hit a two-run homer in the seventh inning to help the Arizona Diamondbacks beat the San Francisco Giants 2-1 on Wednesday night. Greinke (1-2) got his first win with Arizona and remained undefeated against the Giants - he's 8-0 in 11 starts against San Francisco and 3-0 against Bumgarner. Brandon Drury added two hits for the Diamondbacks, who won their fourth straight and have taken 11 of their last 13 in San Francisco.