SAN FRANCISCO — There’s a tune Tim Flannery once sung that he finds perfectly fitting to describe how his San Francisco Giants get the most out of themselves in the postseason.

Old standbys like Buster Posey, Hunter Pence and Pablo Sandoval mix with rookie faces, giving the Giants a seemingly unique ability to win every other October. Quirky circumstances or injured stars don’t seem to matter, whether it’s the 2010 bunch of castoffs and misfits or a pair of veterans making their first World Series trip.

“There’s a line I once sung for Andres Torres: ‘One thing for certain, I promise you will see, it’s never too late to be the person you were meant to be,’ ” Flannery, the thoughtful third-base coach and musician, offered after Thursday night’s National League Championship Series clincher. “And I’ve seen it here. I’ve seen it night after night. These guys come here and we get the most and we get the best out of them.”

Posey, Sandoval, Santiago Casilla and Madison Bumgarner were all with the Giants in 2010, then Pence joined the fun two years later for those remarkable comebacks in the first two rounds of the playoffs and the surprising World Series sweep of Detroit.

Now, these Giants are determined to win it all once more for those who don’t already have a sparkly championship ring.

Tim Hudson, a 16-year pro, is headed to the World Series for the first time. Michael Morse, who hasn’t started since late August because of a pesky oblique injury, delivered a tying home run as a pinch hitter in Thursday’s 6-3 win over St. Louis.

“It’s awesome for them,” shortstop Brandon Crawford said. “They’ve had long careers and not been able to get there before, so I’m happy to be a part of it with them. I’m getting a little spoiled, I guess, I’ve had a couple in only a few years. So for them to get there finally, it’s great for them.”

There’s even one who could fit the “castoffs and misfits” description of the 2010 team: Travis Ishikawa contemplated retirement after he was released by Pittsburgh in April, then re-signed with his original big league team and hit the pennant-clinching homer in October.

General manager Brian Sabean once again made midseason moves for players who became key. Pitcher Jake Peavy overcame his struggles with Boston to thrive under his former skipper in San Diego, Bruce Bochy. But Sabean, at 18 years the longest-tenured GM in the major leagues, considers constructing a core the key.

“You build your team from within. That’s a surefire way to keep things moving forward and prevents you from having to go into the market,” Sabean said.

Hudson, 39, played on his share of successful teams in Oakland and Atlanta, then signed a two-year deal with the Giants because his gut told him he might have the chance to be part of something like this after his 2013 season was cut short by a devastating ankle injury.

On Thursday, Pence called the right-hander to the middle of the clubhouse for a postgame beer salute and the Giants’ take on a 2010 rap song, “Teach Me How to Dougie” — which they’ve changed to “Teach Me How to Huddy.”

“I was trying to drink beer. I’m not much of a talker,” Hudson said. “He kind of put me on the spot, and I clammed up a little bit. I think everybody thinks about it every year when they play. Obviously, to have gone 16 years without having been able to experience something like this, you wonder if it’s going to happen.”

San Francisco slumped in the summer and again through September and still did enough in the final week of the regular season. The Giants reached the World Series without ace pitcher Matt Cain (elbow surgery), center fielder and leadoff man Angel Pagan (back surgery) and second baseman Marco Scutaro (limited to five games this year because of a bad back).

They won in the playoffs with Tim Lincecum, who has struggled since pitching a no-hitter in June.

“That’s just kind of been our personality all year,” Hudson said. “We fought through the hard times. Whether it’s during the season or in the middle of games, we try to find ways to get it done or get over it. It’s just been our MO all year.”