With former President George W. Bush watching from a front-row seat, winner Colby Lewis worked around solo home runs by Cody Ross in the seventh inning and Andres Torres in the eighth. The Giants eventually brought the tying run to the plate, but reliever Darren O'Day retired Buster Posey to end the eighth.
"I was just really excited to come back home. I knew with these fans out here we had a definite advantage," Lewis said. "It was just a thing of comfortability." The Rangers, in the franchise's 50th season, became the first team from Texas to win a World Series game.
Texas manager Ron Washington finally brought in Neftali Feliz in the ninth inning, and the powerful closer earned his first save of the postseason. Washington was criticized in the first two games at San Francisco for leaving Feliz in the bullpen while the Giants broke away.
No team in World Series history has overcome a 3-0 deficit and now Texas won't have to try, either. Rangers starter Tommy Hunter, especially good at home, faces rookie Madison Bumgarner in Game 4 on Sunday.
Lewis picked up where he left off in the American League championship series, where he finished off the defending champion Yankees in Game 6. He's 3-0 this postseason, all of his wins coming after a Texas loss.
Lewis allowed five hits in 7 2-3 innings and struck out six. He stopped a Giants team that had become the first National League team to score at least nine runs in back-to-back Series game.
"We needed a well-pitched job," Washington said.
Moreland, promoted to the majors in late July, won a tough at-bat against Jonathan Sanchez with a three-run homer in the second on the ninth pitch.
Feliz stuck out two in a perfect ninth, setting off a big celebration. Bush leaned over and kissed Ryan's wife as fireworks exploded overhead.
The Rangers looked more like themselves with Vladimir Guerrero back in the designated hitter spot. The other Texas big bats chimed in, with Hamilton hitting his fifth home run of the postseason.
Moreland homered from the ninth spot in the lineup.
"It's a different league, and that's the American League," Giants manager Bruce Bochy said. "Their guy got a big hit." Lewis is a below-.500 pitcher for his career, not including the two seasons he recently spent pitching for Hiroshima in the Japan league. Despite a shaky record, he's known for this trait: He gets tougher in tight situations.
Lewis escaped a two-on jam in the first by getting Pat Burrell to fish for a breaking ball, and worked around a leadoff walk to Ross in the second.
Nelson Cruz opened the Texas second with a double off the center-field wall and eighth-place hitter Bengie Molina drew a walk. It was trouble time for Sanchez - he owned the best hits-to-innings ratio in the NL this year, yet also led the league in walks and can unravel quickly.
Moreland hung in, fouling off four straight 2-2 pitches and barely getting a piece on a couple of them. He then took a smooth swing sent a liner far into the right-field seats for his first career home run against a left-hander.
It was the big hit the Rangers needed to get back into the Series. The crowd roared and Ryan stood up, thrust his right arm in the air and hollered.
Hamilton gave his boss another thrill in the fifth. A bit jumpy at the plate early in the game, the probable AL MVP patiently waited for his pitch and launched a drive deep into the lower deck in right-center field.
Sanchez, who got just six outs against Philadelphia in his previous start, gave up four runs, six hits and three walks in 4 2-3 innings, raising his ERA to 4.05 in four postseason starts. Guillermo Mota, who had started warming up in the third, replaced him.
