SAN FRANCISCO (AP) — The Giants sure are tough to eliminate this postseason.Barry Zito and the Giants gave themself at least one more game in the NL championship series with a 5-0 victory Friday in St. Louis that forced Sunday’s Game 6 back at AT&T Park. Just where the NL West winners want to be with their season on the line — in front of the raucous, orange towel-waving sellout crowd.“It’s great to be back in San Francisco. There is no tomorrow,” Giants right fielder Hunter Pence said. “It’s a unique feeling. It has brought the best out of us.”The wild-card Cardinals traveled out West again for a trip they certainly hoped they wouldn’t have to make. Defending champion St. Louis leads the best-of-seven series 3-2, needing one more win for a World Series return.St. Louis knows how hard winning the last one can be considering what this Giants team already did during these playoffs: winning three straight on the road at Cincinnati in the division series after falling behind 2-0.“They’ve been doing this all year. Obviously, the Cincinnati series, here come the Giants,” Cardinals third baseman David Freese said. “It’s good for TV but it’s disappointing in (our) sense.”Game 2 winner Ryan Vogelsong starts for the Giants for the second time this series against Chris Carpenter, who lost that matchup at San Francisco on Monday.“No question, we want to win it as soon as we can. We wanted to do it last night,” Carpenter said Saturday. “But, again, we have to get one win before they get two. We’ll do whatever we can. If it’s not tomorrow night we’ll come in and do it again.”While the Cardinals took a day to rest — Carpenter and a couple of pitchers did play some catch — Pence and most of his team showed up at the ballpark in late afternoon to hit and work out even though manager Bruce Bochy gave his players the day off.With Vogelsong on the mound, the Giants have to like their chances to push the series to a Game 7.Vogelsong became the first Giants starter to make it through six innings this postseason when he went seven strong innings in a 7-1 Game 2 victory. He allowed four hits and one run for his first career postseason win.“We all kind of feel like we’ve been in this situation before with Cincinnati,” Vogelsong said. “And it’s not over until the last out. I think both teams that are playing right now have proved that in the first round.”Giants general manager Brian Sabean wasn’t surprised to see his team on the field Saturday for an optional practice — realizing full well players didn’t want to risk losing any momentum from the night before.“Sometimes you wonder how much at this stage that there is a home-field advantage,” Sabean said. “In some cases, because of the bullpens, it’s probably as much as whoever gets the lead and can hold off the other ballclub from scoring will win the ballgame. We know what’s at stake. We know that they’re going to put a game against us. I’m sure Vogey will be ready.”St. Louis postseason ace Carpenter was looking forward to another chance, too.He has been plenty reliable this time of year for the Cardinals, with his 10 postseason victories the most in franchise history. His stuff never felt right the last time out against the Giants, when he allowed two earned runs, five in all, and six hits in four innings.“It doesn’t matter if you’re on the road, what game it is, it’s the first one to win four games, and hopefully we can do that tomorrow,” Carpenter said.The 37-year-old Carpenter pitched two clinchers last October and went 4-0. He won the division series clincher and did it again in Game 7 of the World Series against the Texas Rangers.So, why not add that NLCS distinction to his impressive October resume? It’s already been a memorable month for Carpenter, who came back to make three starts — throwing just 17 innings — late in the regular season after a complicated operation that removed a rib and two neck muscles to relieve numbness on his right side.He is counting on commanding his fastball better this time out. His postseason ERA in two outings this year is 1.86.“The last time out my stuff went backwards a little bit,” Carpenter said. “I was trying everything I could to get outs but unfortunately it didn’t work. I had some nice work in between that start and this start, I feel good and I’m looking forward to getting back out there.”The Giants returned to the Bay Area as soon as they could to get ready for Game 6, flying home overnight and landing at 2:30 a.m. But the Cardinals still had to go home after Friday night’s game and pack their bags. They slept in their own beds and took off from St. Louis at midday Central time.San Francisco, which made an improbable run to the 2010 World Series title, hopes to send St. Louis out of town empty-handed. The Giants won the NLCS in five games at their waterfront ballpark against the Cardinals in 2002 before falling short in a seven-game Series to the wild-card Angels. The Detroit Tigers are waiting on their opponent after a four-game ALCS sweep of the New York Yankees.Not that Bochy or Cardinals manager Mike Matheny can even think that far in advance, just yet.“I don’t necessarily see them as pesky as much as just talented,” Matheny said of the Giants. “And the same kind of makeup that we have, they aren’t going to go away and neither are we. And we knew that going into this thing. As soon as we won a couple of games at home there was nobody in there for a second under the belief that this was going to be a team that was going to just roll over. So we know that this team has the ability to do what they did, once again, in Cincinnati, running in there and doing something that hasn’t been done all season. ... It’s just a matter of execution, and they executed better than us yesterday.”