The 6-foot-8 Fister managed to stay on the mound, and even excelled. Bumgarner more than matched him, however, allowing just two hits before the San Francisco bullpen closed it out before another pulsating crowd.
Santiago Casilla pitched a perfect eighth and Sergio Romo worked the ninth for a save in the combined two-hitter, leaving Triple Crown winner Miguel Cabrera in a huge hole heading back to Comerica Park. Anibal Sanchez will start for the Tigers against Ryan Vogelsong in Detroit.
The Tigers looked foggy at the plate, maybe still lost following a five-day layoff after an ALCS sweep of the Yankees. Cabrera hopped up and twisted away after third baseman Pablo Sandoval, who homered three times in the opener, snared his early line drive.
Bumgarner had something to do with the Tigers' troubles, too.
Bumped from the NLCS rotation after two poor postseason starts, he returned with a flourish. The left-hander struck out eight and looked as sharp as he did in the 2010 World Series when, as a 21-year-old rookie, he stopped Texas in Game 4 on the way to a championship.
This game was scoreless in the seventh when the Giants went ahead, right after actor Tom Hanks — a former peanut vendor at the nearby Oakland Coliseum — sang "Take Me Out to the Ball Game" on the field.
Pence led off with a single and Fister departed, getting lots of hugs in the dugout. Rookie reliever Drew Smyly walked Brandon Belt on a full-count pitch and Blanco's bunt loaded the bases.
The Tigers kept their infield back up the middle, and had no play at the plate on Crawford's bouncer.
Pence added the insurance run the next inning with his flyball off Octavio Dotel.
Fielder and the Tigers came up inches short of taking an early lead, the result of yet another alert play by second baseman Marco Scutaro and a dubious decision by third base coach Gene Lamont.
Fielder was hit by a pitch to lead off the second, Delmon Young followed with a double and when the ball rattled around in left field, Lamont waved the burly slugger home. Even with no outs, Lamont sent him.
Scutaro, in the middle of every big play for the Giants this month, dashed across the diamond, caught Blanco's relay and unleashed a strong throw to the plate. All-Star catcher Buster Posey made a swipe tag to Fielder's backside, just as the Tigers star slid home. Umpire Dan Iassogna had a clear look and made a demonstrative call — out!
Fielder immediately popped up from his slide and pleaded his case with two hands. Tigers manager Jim Leyland rushed out and pointed to the plate. At second base, Young yelled, "No!"
But even if there was replay review, it wouldn't have helped the Tigers. Because TV replays showed Iassogna, working his first plate job in a World Series, got it right.
There was no dispute that Fister somehow avoided a serious injury moments later.
With two outs in the Giants second, Blanco lined a shot up the middle that hit Fister on the right side of the head and deflected on the fly to shallow center field.
Fister showed no visible effect from the blow — in fact, some in the crowd wondered whether the ball perhaps glanced off his glove because Fister stayed on his feet. Only when fans saw replays did groans echo around the ballpark.
Leyland, pitching coach Jeff Jones and a trainer went to the mound, and Fister insisted on staying in the game. He walked the next batter to load the bases, but retired Bumgarner on a popup, starting a streak of 12 straight hitters set down by Fister.
Among those who winced was Oakland pitcher Brandon McCarthy, who sustained a skull fracture and brain contusion after being hit by a line drive last month.
"I'm not watching but did just see the replay. Certainly hope he's ok," McCarthy tweeted.
NOTES: Bumgarner struck out Austin Jackson and Omar Infante to start the game. Two other Giants fanned the first two batters in a Series game: Christy Mathewson (1905) and Carl Hubbell (1933). ... Bumgarner picked off Infante at first base to end the fourth. Infante made a break for second and, like Fielder earlier, came up short with his slide. ... Scutaro was the only Giants hitter to have previously faced Fister. ... Posey has a hit in all seven World Series games in his career.
KQED's live blog of Game 2: