PHOENIX -- Pablo Sandoval is swinging a hot bat recently -- even when the Giants’ veteran infielder begins a game on the bench.

Sandoval contributed to a breakout game for San Francisco’s offense Saturday night, hitting a pinch-hit home run in the eighth inning of an 8-5 win over the D-backs at Chase Field. The Giants had lost five of their previous seven games and were coming off a lopsided shutout loss in Friday’s series opener.

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Sandoval’s home run was one of several big moments that led to a strong all-around showing for San Francisco. Here were the three keys to the Giants’ bounce-back victory.

1) Giants get on the board early

Early offense has been rare for the Giants this season, particularly in the first inning. Entering Saturday, they had scored in the opening frame in only five games, amounting to six runs, their lowest output of any inning.

However, that wasn’t a concern Saturday. Evan Longoria put the Giants up, 1-0, with an RBI single in the first. They added on shortly after, scoring three runs in the third on an RBI triple by Steven Duggar, an RBI single by Buster Posey and a Brandon Crawford sacrifice fly.

“I thought we brought a sense of urgency early, and it just kind of permeated,” Duggar said. “I think it was just kind of the vibe. Nobody really said anything, it was just kind of the way guys went about their business early.”

The Giants improved to 8-3 when scoring first. The early runs sparked a big offensive night as eight batters contributed to 11 hits, with Duggar, Posey and Brandon Belt each collecting two from the Nos. 2, 3 and 4 holes.

“Longo got us started with his base hit and it just seemed like we rolled from there,” manager Bruce Bochy said. “We got some timely hits.”

2) Dyson bails out Bumgarner

Madison Bumgarner was having one of his better starts of the season, allowing only two runs through six innings and appearing to be on his way to the first seven-inning start by a Giants hurler since April 13.

But the D-backs rallied in the seventh and brought an abrupt finish to Bumgarner’s night. The left-hander created a jam with a pair of walks, and his night ended when he allowed a one-out, pinch-hit RBI double to John Ryan Murphy.

The Giants turned to Sam Dyson to diffuse the situation as the righty entered with runners on second and third and one out, looking to preserve a three-run lead. Although a run scored on an Adam Jones groundout, Dyson kept San Francisco’s lead at 6-4 after seven innings.

Bumgarner didn’t record his fourth straight quality start and he allowed at least four runs for the sixth time in 10 outings. But Dyson and the offense helped the Giants’ ace notch his third win of the year.

“The only reason I’m here is to win,” Bumgarner said. “I feel like I’m throwing the ball as good as I ever have, and the results not being there to match up is frustrating. But when our offense is putting up eight [runs], it’s a little easier to deal with. Like I said, it’s about winning, and that’s it.”

3) Panda swings the momentum

Shortly after the D-backs cut the Giants’ lead to two in the seventh, Sandoval took back the momentum. With two outs in the eighth, he slugged his sixth homer of the season, which was his second career pinch-hit home run.

Sandoval’s solo blast, his third homer in five games, provided a big insurance run. Over his last six contests, he is 8-for-19 with five extra-base hits and six RBIs.

“It’s nice to start him, but when he doesn’t start, it’s nice to have him come off the bench, too,” Bochy said. “You look at our offense, he’s the silver lining through our struggles, I think, because he’s done a nice job coming off the bench or starting.”

The Giants added another run on Belt’s two-out solo homer in the ninth.