The teams traded two-run home runs through the first six innings and the Diamondbacks finally broke through in the 11th to salvage the finale of a three-game series.
Miguel Montero reached on a ground-rule double to open the 11th off Craig Stammen (4-3) and was replaced by pinch-runner A.J. Pollock. Cody Ross sacrificed Pollock to third and Jason Kubel drew a walk, bringing up Gregorius.
On a 1-1 pitch, the left-handed hitting Gregorius reached across the plate to put down a bunt on a pitch that was out of the strike zone. Pollock didn't break from third until he saw that Gregorius had put the bat on the ball and the bunt turned out to be such a good one that Gregorius beat it out for a single.
There was no play at the plate on Pollock.
Josh Collmenter (4-0) worked the 10th to get the victory and Heath Bell came on the 11th and earned his 14th save.