Fister ended up with the hard-luck loss when he allowed a leadoff single to Hunter Pence in the seventh and reliever Drew Smyly was unable to strand him in part because of a perfect bunt that never rolled foul.
It was remarkable that Fister was even in the game that long after it looked as if he could have been knocked out in a scary moment in the second inning. Gregor Blanco hit a line drive that struck Fister just above the right ear with a runner on first and two outs. The ball ricocheted into short center for a single.
"Whoa!" umpire Dan Iassogna said as he popped out from behind the plate, adding: "Doug, you OK?" when he got to the mound.
"I was scared to death when it happened," Tigers manager Jim Leyland said. "I didn't really realize exactly how it hit him. It kind of grazed I want to say the side of his head, the back of his head. It was a scary moment, obviously, but he was fine."
Fister looked unfazed by the blow and remained in the game after being checked out by a trainer, Leyland and pitching coach Jeff Jones.
"They asked me the typical concussion questions. He obviously saw in my eyes I was OK," Fister said. "I'm not concerned. I have a minor bump. According to my dad my whole life his saying has always been if I got hit in the head I'd be OK. That's how I take it."
Fister answered every question correctly on the mound and even added that he would get the third out.
"He didn't seem scared," first baseman Prince Fielder said. "He definitely showed some toughness."
Fister then walked Brandon Crawford to load the bases but escaped the jam by retiring fellow pitcher Madison Bumgarner on a soft looper to shortstop Jhonny Peralta.
The 6-foot-8 right-hander didn't allow another hit until Pablo Sandoval singled with two outs in the sixth, retiring 12 straight batters after the walk to Crawford.
"It was scary at the moment but then he seemed to shake it off," catcher Gerald Laird said. "This guy's tough. I was surprised. The way (the batter) hit it and the way it hit his head, it was scary. For him to bounce back and pitch like he did, that says a lot about him."
Leyland sent Fister back out for the seventh with 108 pitches to face the right-handed hitting Pence before a run of three straight lefties came to the plate. Pence ended Fister's night with a single to left field on his 114th pitch.
That proved costly. Smyly walked Brandon Belt, and Blanco reached on a bunt single that Smyly, Laird and third baseman Miguel Cabrera tried to will foul. But the ball tantalizingly stayed on the dirt between the foul line and infield grass before rolling to a stop in fair territory, loading the bases with no outs for the Giants.
Leyland chose to play the middle of the infield back to avoid a big inning. But that decision allowed a run to score when Brandon Crawford bounced into a 4-6-3 double play.
"It's not debatable to me," Leyland said. "Some people might debate that, but I felt we had to take our best shot to come out of it with one run because if we don't score, it doesn't make any difference anyway."
Fister allowed one run and four hits with one walk with three strikeouts. He became the first Tigers pitcher to last at least five innings in five straight postseason starts. But he is winless in three postseason outings this year because the bullpen blew leads his first two times on the mound.
"It was a tough night," Fister said. "Obviously we had a couple of balls that didn't go our way. It's OK. We're going to come back."
The Tigers now find themselves in a daunting 2-0 hole because the offense generated nothing against Bumgarner and the bullpen. Only one World Series team has overcome such a deficit since the New York Mets did it in 1986.
Detroit's best chance at scoring was thwarted by another questionable decision. With the burly Fielder at first base and no outs in the second, Delmon Young grounded a double down the left-field line. Blanco picked up the ball after it caromed off the fence in foul territory and threw to second baseman Marco Scutaro near third base.
Third-base coach Gene Lamont waved Fielder home and he was tagged out by catcher Buster Posey just before touching the plate. Fielder had been sent home from first just three times on 10 doubles. The fourth one proved costly.
"We wanted to be aggressive, and I think he got just a little overaggressive, and it was a bang-bang play," Leyland said.