The Giants have progressed toward the postseason by relying on an offense that's lacking in power but still dynamic. They're capable of sustaining sudden and effective bursts of hitting, reflected largely by the club's Major League-high .308 batting average with runners in scoring position since the All-Star break.
Their third-inning uprising featured unlikely elements, as well as just plain luck. These sorts of things tend to happen to winning teams.
Matt Cain, who struggled with his control while lasting two batters into the sixth inning, benefited from a similar lapse by Arizona starter Tyler Skaggs (1-2) when he walked to open the third. One out later, Marco Scutaro hit a grounder up the middle that D-backs shortstop John McDonald dove for and grabbed. But second baseman Aaron Hill couldn't handle McDonald's low, glove-handed relay as Cain slid hard into the bag to break up a double play and assure Scutaro of a hit. Pablo Sandoval, who rebounded from his one-day benching by going 3-for-5, singled to center to load the bases.
Buster Posey then hit a slow roller to third base. Ryan Wheeler threw home, but Cain beat the relay with a hard, feet-first slide that gave Posey his 90th RBI of the season.
Up came Pence, who hammered Skaggs' 2-2 fastball into the left-field seats for his third career grand slam. Pence has provided 34 RBIs with only 37 hits for the Giants while batting just .233 in 41 games.
Pence showed Skaggs, a rookie making his fifth career start, how accomplished hitters stay determined through an at-bat.
"He fouled off two really good pitches," Skaggs said. "I threw a pretty good curveball I thought was a strike, but you have to tip your cap to him."
Meanwhile, Pence relished the opportunity to lead the Giants' charge.
"That's the feeling we have every game," he said. "We feel like we're going to put something together if we keep plugging away."
Cain (14-5) survived a first inning in which he threw 34 pitches, left the bases loaded and walked three batters -- a number that he had reached in only four previous starts this season. He received help from Posey, who threw out Adam Eaton on an attempted steal of third base. Justin Upton's foul popup finally gave Cain his improbable scoreless inning.
Cain lamented walking Eaton and Paul Goldschmidt after forging ahead 0-2 on each hitter.
"Maybe I got a little too fine with some pitches instead of using the advantage of being ahead in the count," Cain said.
Cain vanished after hitting Miguel Montero and yielding Upton's single to open the sixth inning. Jose Mijares allowed pinch-hitter Chris Johnson's RBI single and Guillermo Mota hit McDonald to load the bases. Then third baseman Sandoval made a diving, backhanded catch of pinch-hitter Chris Young's line drive to prevent an extra-base hit that would have scored multiple runs.
"If that ball gets down the line, it's a different ballgame," Giants manager Bruce Bochy said.
Jeremy Affeldt replaced Mota and ended the rally by coaxing Eaton's comebacker for a forceout at home and striking out Hill. But Affeldt wasn't the last Giants reliever to excel. Santiago Casilla not only pitched 1 1/3 scoreless innings, but he also grounded a bases-loaded, two-out single off Matt Lindstrom in the eighth inning for his first career hit and the Giants' final run.
It was Casilla's third career plate appearance, which may have accounted for his high-stepping running style and his obvious confusion after crossing first base.
"I think we were all shocked, really," said Bochy, who initially ordered Casilla not to swing before relenting.
"All that hard work he's been doing," Affeldt said in mock wonder.