Sandoval's score on a Eugenio Velez single sent the Diamondbacks to their ninth straight road loss, one shy of a club record. It also put Arizona 2 1/2 games behind the Los Angeles Dodgers for first place in the National League West. Los Angeles beat San Diego 6-2 Tuesday.

The Giants won despite stranding 15 runners.

Arizona catcher Chris Snyder's two-run homer off Brian Wilson (3-2) had tied the game in the top of the ninth.

Giants starter Barry Zito struck out nine and allowed five hits and two runs over six innings. Doug Davis gave up six hits and two runs through 5 1/3 innings for Arizona but the loss went to reliever Jon Rauch (4-7).