SAN FRANCISCO -- Whenever Zack Greinke takes the mound at AT&T Park, he defaults to his dominant form. That trend continued Saturday, when Greinke spun eight innings of two-hit ball to lower his career ERA in San Francisco to 1.37. Paul Goldschmidt delivered all the offense Greinke needed with a two-run homer in the first to power Arizona to a 2-0 triumph.

"He does it every time," D-backs manager Torey Lovullo said. "It's a very nice feeling when you're putting him out there [that] he's going to give you everything he has, he's going to have a terrific game plan and he's going to execute."

Greinke, who also hit two doubles, struck out eight and walked one, giving him a game score of 90. It's just the second time in his career that he's had a game score of 90 or higher, with the other time being when he had a 91 on July 13, 2013.

"I felt good, [but] location was probably the better part about it, and I mixed it up really good," Greinke said. "A really good mix and good location was the key."

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Goldschmidt's 35th homer, which had an exit velocity of 111.3 mph and traveled 438 feet, was the hardest blast Giants starter Madison Bumgarner has given up since Statcast™ debuted in 2015. It came on the first pitch the first baseman saw in the game.

"As good as Madison is, you can't spot him strikes, so I was trying to get something that was in the middle of the plate and try to hit it hard," Goldschmidt said. "Honestly, I was just trying to get on base, but I was able to get it up in the air and get it out of here."

Added Bumgarner, "It came maybe a little more on the plate than if you're going to walk up there and set it in a spot. But it was a pretty decent pitch. He's a good hitter."

The win lowered the D-backs' magic number for a postseason berth to six and helped them remain five games ahead of the Rockies for the top spot in the National League Wild Card race. Arizona is now 25 games over .500 for the first time since capping the 2011 season with a 94-68 record.

Bumgarner (3-9) has now lost four consecutive games for the first time in his Major League career. He's surrendered 14 home runs in 12 starts since returning from the disabled list and tossed seven innings of two-run ball Saturday.

"Things just haven't worked out for us this year," Bumgarner said. "It's frustrating for everybody. [The fans] have done a great job, though. They make it fun. The sellout streak's gone -- whatever. The stadium is still pretty full. It's still an awesome place to come pitch."

Joe Panik and Brandon Crawford delivered the lone hits for San Francisco, which must go 6-6 in its remaining 12 games to avoid 100 losses.

MOMENTS THAT MATTERED

Slamming the door:Mac Williamson reached on an error by Kristopher Negron to open the sixth, opening the door for arguably San Francisco's best shot at a run. Bumgarner struck out in the next at-bat, Denard Span moved Williamson to second and red-hot Panik walked to set up Jarrett Parker with the chance to break up Greinke's shutout. But Greinke prevailed, striking out Parker on a curveball to escape the jam.

"He really limited the damage, and he picked up his teammates," Lovullo said. "I thought it was a really, really good outing."

"We got a break, but it ended pretty quick there, unfortunately. ... We just couldn't get that run in," Giants manager Bruce Bochy said. "You're two runs down. It just takes a hit, a double or something to get you going. We couldn't do it. It's hard to win a ballgame with two base hits."

Back-to-back K's: The D-backs were looking to add a few insurance runs in the seventh off Bumgarner, but ran up against the left-hander's strikeout ability. Brandon Drury doubled leading off the inning and Negron walked two batters later. But Greinke and David Peralta both struck out, cutting the rally short to give the Giants a shot at erasing the two-run deficit.

QUOTABLE

"I thought that was the key to the game. You don't know how many you're going to get off of Madison Bumgarner. You have a good approach off him all night and still you don't get some great results, so Goldy walked up to home plate ready to hit and gave us that two-run lead, and Zack took it over from there." -- Lovullo, on Goldschmidt's homer

"It's hard sometimes to find a silver lining through a year like this, but the fact that he did come out of this accident OK. He's back healthy and we'll have him back next year." -- Bochy, on Bumgarner, who missed three months after a dirt-bike accident in April

SOUND SMART WITH YOUR FRIENDS

Greinke roped two doubles in his three at-bats, becoming the third pitcher in D-backs history to tally two or more extra-base hits in a game. Dan Haren was the last to accomplish the feat on May 21, 2010 vs. Blue Jays (two doubles).

It also makes Greinke 7-for-15 at AT&T Park in his career with three doubles and a homer.

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WHAT'S NEXT

D-backs: Arizona will send right-hander Taijuan Walker (9-7, 3.32 ERA) for Sunday's 1:05 p.m. MST series finale. In his last five starts, Walker is 3-0 with a 1.26 ERA, having allowed four runs in 28 2/3 innings.

Giants:Chris Stratton will get another shot at a start after facing just one batter amid a lengthy lightning and rain delay when the Dodgers were in town. Like Walker, Stratton has done well recently, posting a 2-1 record and 1.96 ERA over his last five starts.

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