The Cards had to win a one-game showdown against the Braves to earn the right to face the National League East champion Nationals, who were one out from moving on to the NL Championship Series when the Cardinals staged another of their implausible rallies to seize Game 5 by a 9-7 verdict, rendering D.C. and its environs demoralized.
"Hopefully, we can take this to the next series," Cards manager Mike Matheny said as the fluids flew and voices roared in the visitors' clubhouse close to an hour after midnight, Saturday having arrived.
The Cardinals and Giants split six games this season, two in San Francisco in May, four in St. Louis in August. The Giants have home-field advantage as NL West champions, but they've seen how intimidated the Cardinals are by unfriendly environs.
Not at all.
St. Louis will go into this NLCS understanding that it can't let one man -- San Francisco catcher Buster Posey -- impose his will. The Cards saw what the man did this season.
A favorite for the NL Most Valuable Player Award, Posey hit .476 against Cardinals pitching, with two homers and six RBIs in six games. He had .577 on-base and .810 slugging percentages, for a 1.386 OPS.
Posey is riding high, his grand slam off the Reds' Mat Latos having powered the Giants to their Game 5 triumph in Cincinnati on Thursday.
With Jaime Garcia sidelined, the Cards don't have any lefties in the rotation to throw at Posey, who kills southpaws -- he hit .433 against them with a .793 slugging percentage in 164 at-bats.
The Cardinals will go with Lance Lynn, Chris Carpenter, Kyle Lohse and Adam Wainwright against the Giants, who won 94 games in the regular season, six more than St. Louis, to take the West by eight games.
The Cards beat Giants southpaw Madison Bumgarner in San Francisco in May, with David Freese going deep among his three hits. Then Matt Cain outdueled Wainwright for a split.
Posey went 5-for-8 in the two games. Matt Holliday homered off Cain, and Yadier Molina went deep against Sergio Romo, the Giants' closer.
That's something to file away if Romo is summoned to dispatch the heart of the Cardinals' order -- Holliday, Allen Craig, Molina and Freese -- to protect a lead.
In St. Louis in August, the Cards knocked out Cain with five runs in five innings, with Carlos Beltran going deep. But the Giants took the next two games behind Barry Zito and Ryan Vogelsong, including a 15-0 rout in which Marco Scutaro drove in seven runs. Craig homered twice off Zito.
The Cardinals looked to Wainwright to salvage a split of the four-game series, and he came through with a 3-1 decision. Beltran's homer off Bumgarner in the first inning was the difference.
"We're looking forward to the next series," Molina, the Cards' leader, said. "We want to keep playing, keep going."
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.