CINCINNATI — The entire season was a comeback for Buster Posey, so he didn't think anything of it when San Francisco needed one of the biggest yet to play for a pennant.
He led them to one of Giant proportions.
The National League batting champion hit the third grand slam in Giants postseason history on Thursday, sending San Francisco back to the championship series with a 6-4 victory over the Cincinnati Reds.
They will play Game 1 on Sunday, either in Washington against the Nationals or in San Francisco against the wild card St. Louis Cardinals. They planned to stick around town until the Nationals-Cardinals series, tied 2-all, is decided on Friday.
Matter which one?
"We could go up against anybody at any time," shortstop Brandon Crawford said. "Being down 2-0 and coming back and winning three at their place, it's an unbelievable feeling."
The Giants became the first NL team to overcome a 2-0 deficit in the division series, which began in 1995. Major League Baseball's changed playoff format this season allowed them to become the first to take a best-of-five by winning the last three on the road.
San Francisco won the World Series in 2010 without trailing in any of its postseason series. The Giants took four of five from Texas for their sixth title and their first since they moved from New York to San Francisco in 1958.
They've really had to scramble this season to get another shot at it.
Their bullpen took a huge hit when closer Brian Wilson blew out his elbow, and that was just the start. All-Star game MVP Melky Cabrera got a 50-game suspension in August after a positive testosterone test, taking a .346 hitter out of their lineup. The Giants have decided not to bring him back, even though he's eligible to return for the NL championship series.
Two-time Cy Young winner Tim Lincecum pitched so poorly — 15 losses — that he got relegated to the bullpen for the division series.
And don't forget that Posey was coming off a broken leg that wiped out most of his 2011 season, making a great comeback of his own.
"Unreal," said Sergio Romo, who fanned Scott Rolen with two runners aboard to end it. "That guy's definitely the MVP of our team. We believe he's the MVP of the league. We wouldn't be here without him, that's for dang sure. He's the one that's been the face of the team all season long. What a great story with all he's been through last year."
Posey's second career grand slam, off Mat Latos, put the Giants up 6-0 in the fifth and sparked a joyous scrum in the San Francisco dugout. The ball smacked off the front of the upper deck in left field, just above Latos' name on the video board.
For the first time in the series, the Giants could exhale.
"I don't think anybody gave up," Posey said.
Will Clark, in the 1989 NLCS, and Chuck Hiller, in the 1962 World Series, hit the other Giants slams in the postseason.
Matt Cain and the bullpen held on, with more help from Posey. The All-Star catcher threw out Jay Bruce at third base to snuff out a sixth-inning rally that cut it to 6-3. The Giants had a pair of diving catches that preserved the lead in the eighth.
There was more drama in the ninth. Ryan Ludwick singled home a run before Romo got Rolen swinging to end it.
The Giants raised their arms, hugged and huddled by the side of the mound, bouncing in unison.
"It was a spectacular moment," outfielder Hunter Pence said.
In Cincinnati, the home-field meltdown had a sickeningly familiar feeling. The Reds haven't won a home playoff game in 17 years. After taking the first two on the West Coast, all they needed was one more at home, where they hadn't dropped three straight all season.
"You get tired of the disappointments, but then you get over it," manager Dusty Baker said. "It hurts big-time."
Once Posey connected, the Reds were the ones facing a steep comeback. They've never overcome a six-run deficit in the playoffs, according to STATS LLC.
Couldn't do it this time, either.
"Buster Posey's swing was a series-changer," said Reds star Joey Votto, standing on second base when the game ended. "That made it very difficult to come back. You know they're going to throw the kitchen sink at us."
The Reds won't forget the first inning of the series, when everything changed. Ace Johnny Cueto pulled muscles in his right side and had to leave the game. Latos pulled them through that opening game, pitching in relief on short rest for a 5-2 win.
He couldn't get them another one, or end that 17-year streak of futility.
NOTES: Posey's other career grand slam came on July 7, 2010, at Milwaukee. ... The Reds are 3-3 in winner-take-all playoff games, including 1-2 in best-of-five series and 2-1 in best-of-seven series. .. Teams that lose the first two games in a best-of-five series are 8-58 all-time. ... Cain gave up six hits and three runs in 6 2-3 innings, the longest appearance by a Giants starter during the series.
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