Christian Walker hit a three-run homer off a frustrated Carlos Rodón and the Arizona Diamondbacks handed the San Francisco Giants their sixth straight loss, 7-3 Tuesday night. The Diamondbacks (44-53) won for the fifth time in eight games against the Giants this season after winning just twice in 19 meeetings last year. San Francisco (48-49), which won 107 games a year ago, fell below .500 for the first time this season.