SAN FRANCISCO - A pair of grand slams provided bookends to a crazy week in a crazy season for the San Francisco Giants.

All seemed lost following a heartbreaking, 14-inning defeat to the Rockies in Denver on Aug. 24, when Ryan Spilborghs’ game-ending slam lifted Colorado to a 6-4 victory after the Giants scored three runs in the top of the inning.

A mere six days later, San Francisco rode the high of Edgar Renteria’s go-ahead grand slam that carried the Giants to a home sweep of the Rockies and into a tie for the NL wild-card lead with Colorado.

Boom, just like that, the Giants are right back in it.

“It’s a huge boost for us,” reliever Jeremy Affeldt said. “Big wins come in September. Any time right now they’re going to rank up there. They all count, but these wins are big for momentum.”

Speaking of September, it’s been five years since San Francisco played for something in the season’s final month. Now, the Giants are in the heart of a pennant race, the contender general manager Brian Sabean and skipper Bruce Bochy believed they could be from the start.

This is a club that desperately wants to be remembered for much more than Randy Johnson’s 300th win in June or Jonathan Sanchez’s no-hitter in July. That’s because what people recall from recent seasons around here are the tremendous individual accomplishments: Barry Bonds’ home run record in 2007 and a Cy Young Award season by Tim Lincecum last year.

“This is what you play for, what you talk about early in the season,” Bochy said. “We’re approaching September and playing a lot of important games.”

Barry Zito can’t quite believe it’s been so long since the Giants were in the chase — “Really?” he said in disbelief — but he’s only been part of the past two losing seasons in San Francisco.

The Giants have already exceeded expectations in a year that was supposed to be more about rebuilding with a young roster than challenging the first-place Los Angeles Dodgers in the NL West.

Pablo Sandoval, the free-swinging slugger they call Kung Fu Panda, has sparked the lineup with a genuine enthusiasm and energy that undoubtedly makes him the anti-Bonds.

“It’s an important year for us,” Sandoval said. “We have a good team. We’ve got a very good pitching staff. We’ve got a good offense. It’s one of those years you think the team can go to the playoffs and the World Series.”

The Giants hope to get the Big Unit back from a shoulder injury sometime in September, though Johnson is likely to pitch out of the bullpen after missing two months. They should add Brad Penny soon, bolstering an already standout rotation.

Veteran infielder Rich Aurilia has been part of a handful of pennant races with the Giants, and the club’s run to the 2002 World Series. Johnson, Bengie Molina, Renteria, Aaron Rowand and Juan Uribe all own championship rings. Renteria had the winning hit for the Marlins off Cleveland’s Charles Nagy in Game 7 of the 1997 World Series.

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That means little now, yet Bochy hopes that experience will help his club as the Giants make a playoff push.

“These guys know what’s at stake,” he said.

The last time the Giants were in the race — in 2004 — they lost their bid for a playoff spot on the season’s final day despite winning their last game.

Once Houston beat Colorado 5-3, the Astros earned the wild card while the Giants were out of it even before they beat the NL West champion Dodgers 10-0.

“We’ve had a lot of guys who have been in this position before but we’ve also got a lot of guys who have never experienced anything like this,” Aurilia said. “We hope that they can adapt to the difference in playing games in this situation and this type of magnitude than playing games that are meaningless at this time of year.”

Giants owner Bill Neukom is paying close attention to every development, from the triumphs to the disappointments. He has been a regular fixture lately behind the batting cage before games, assessing his club. He has said he will wait until after the season to evaluate Sabean and Bochy — and both of their futures with the franchise could depend on how the team plays down the stretch.