SAN FRANCISCO » Buster Posey and the Giants already know how to win in October — even without all this help from the St. Louis Cardinals.

Strange as it might look sometimes, San Francisco finds a way to score just enough.

Posey drove in three runs and capped another unusual rally as the Giants took advantage of some clunky defense by first baseman Matt Adams in beating the Cardinals 6-4 on Wednesday night to move within one victory of the World Series.

"We might find some weird ways to score runs, but we’re getting people on base first. That’s the main thing," Brandon Belt said.

Chasing their third title in five years, the Giants lead the best-of-seven NL Championship Series 3-1 after poor throws cost the Cardinals yet again.

October ace Madison Bumgarner can pitch San Francisco to another pennant Thursday at home in Game 5. Struggling All-Star Adam Wainwright starts for St. Louis, now facing the same daunting deficit the Giants overcame to beat the Cardinals in the 2012 NLCS.

Kansas City awaits the winner after completing its ALCS sweep of Baltimore earlier in the day. The wild-card Royals will host Game 1 of the World Series on Tuesday night.

San Francisco climbed out of an early three-run hole, and back-to-back bad throws by Adams in the sixth inning helped the Giants rally — one night after a wild toss by St. Louis reliever Randy Choate allowed the winning run to score in the 10th inning.

"I think any time you can put pressure on the defense, you’ve got the opportunity for good things to happen," Posey said. "We’re able to come up with some big two-out RBIs to get back in the game."

Minus injured catcher Yadier Molina again, the Cardinals were clinging to a 4-3 lead when San Francisco put runners at second and third in the sixth. Playing in with one out, the lumbering Adams backhanded Gregor Blanco’s bouncer and stumbled as he tried to set himself to throw home.

Adams had trouble with the transfer, and his toss short-hopped catcher Tony Cruz as Juan Perez slid across with the tying run.

Joe Panik then hit a grounder right to Adams, who stepped on first base before firing wildly to second in trying for a double play. Brandon Crawford stopped between third and home, yet was able to score easily when Adams threw wide of the bag.

"That’s kind of fitting of how our postseason’s been," Panik said. "It might not be the prettiest way of scoring runs."

Cardinals shortstop Jhonny Peralta came way off the base to catch the ball, but had no play at the plate.

"The play at home, there’s a fast runner at third and I was going in on the ball and threw on the run," Adams said. "Just should’ve made the throw, though. The second one, I should’ve just touched first and checked home."

Posey added an RBI single off Seth Maness to make it 6-4. The star catcher also had a sacrifice fly in the first and a run-scoring single in the third.

These wild-card Giants joke about not needing hits and home runs to win, and they’re showing that with timely bunts, small ball and a few miscues from the opponent. The tying and go-ahead runs came home on balls that didn’t leave the infield.

The Giants have scored 12 of their 22 runs over their past six postseason games without the batter getting a hit.

"If you’re not hitting the long ball, you have to find ways to manufacture runs," manager Bruce Bochy said.

Yusmeiro Petit pitched three scoreless innings to win in relief of an ineffective Ryan Vogelsong. Petit has been a valuable long man — he delivered six shutout innings in an 18-inning NLDS victory at Washington.

"He’s been really good for us for a long time and he’s finally getting some recognition. What a weapon to have," Posey said.

Sergio Romo worked the eighth and Santiago Casilla finished for his second save of the series.

A total of six Giants relievers held St. Louis scoreless over the final six innings.

Marco Gonzales took the loss after issuing a leadoff walk to pinch-hitter Perez in the sixth and giving up a single to Crawford.

The Giants haven’t homered in six games since Belt connected in the 18th inning at Washington, but it hasn’t mattered much.

"A lot of these innings are set up with good at-bats early in innings," said Hunter Pence, who had an RBI single in the third.

Cardinals rookie Kolten Wong showed off more postseason power, but his solo homer was wasted.

Vogelsong was the only pitcher in major league history to yield no more than one run in his first five postseason starts, but his streak ended when he gave up four in three innings. San Francisco has still won all six of the postseason games he has started.

SANDOVAL’S STREAK

Giants 3B Pablo Sandoval has reached base in 22 straight postseason games dating to Game 4 of the 2012 NLDS on Oct. 12, 2012. That breaks Barry Bonds’ franchise record set from 2002-03. Bonds set down his crutches post hip surgery to throw out the ceremonial first pitch Wednesday.

UP NEXT

Cardinals: Wainwright believes he has worked out some kinks in his delivery that have kept him from getting out of the fifth in his first two playoff starts this year. He has allowed eight earned runs and 17 hits in nine innings. "I just don’t want to get a bad rap for not being a good playoff pitcher," Wainwright said. "That’s the time I want to shine the most."

Giants: Bumgarner gave up four hits over 7 2-3 innings for a 3-0 win in Game 1. He pitched a four-hitter in San Francisco’s 8-0 wild-card win at Pittsburgh before taking the loss in Game 3 of the NLDS against Washington.