St. Louis ? Albert Pujols made the first big dent in this World Series, then it was Mike Napoli’s turn.

Bases loaded, eighth inning, tie game. A ballpark full of fans on their feet, “Nap-Oh-Lee” flashing on the scoreboard, crowd chanting his name.

And boy did he deliver. A booming double that put his Texas Rangers one win from their first championship, a gigantic hit that moved him closer to possibly becoming the Series MVP.

Napoli and the Rangers can close out the St. Louis Cardinals in Game 6 at Busch Stadium tonight. If they do, the catcher who was traded twice within a week in January will be a central part of the lore.

It happens every fall. Someone steps up — maybe a monster talent like Pujols, perhaps a good player like Napoli given a chance when the stars align. Might even be a fringe guy — Allen Craig for St. Louis this year, Cody Ross for San Francisco the last time around.

A huge swing or two or three, a masterful job on the mound, a sparkling play in the field can do more than win a game. They can create a legacy that lasts forever.

Just ask “Mr. October.”

“It absolutely can define a career,” Reggie Jackson said by telephone this week. “I’m not saying whether that’s right or wrong, but that’s how it happens.

“What year did Babe Ruth call his shot? 1932? You still see kids out there, calling their shot. That game wasn’t on TV, those kids didn’t see it. But they’ve heard about it, they know about it all these years later.”

Jackson hit a Game 7 home run in a 1973, then earned a nickname for life when he homered three times in the Series-clincher in 1977.

Suppose he’d done a little less, say, hit three balls off the wall at Yankee Stadium on that signature night. Would he still be “Mr. October?”

“Probably not,” he said.

Already a three-time NL MVP, Pujols put on what many called the greatest hitting show in postseason history when he tied Series records with three home runs, six RBIs and five hits during the Cardinals’ romp in Game 3.

Those are Pujols’ only hits in the Series so far, with Texas often pitching around him or issuing intentional walks. Yet if the Cardinals win the championship, chances are his pulverizing performance will be featured in the highlights for years to come.

Former Dodgers star Orel Hershiser stamped his greatness by going 3-0 with a 1.05 ERA in the postseason and leading Los Angeles to the title in 1988.

“It is fair to judge someone that way because these are the most important games of your life,” Hershiser said at Rangers Ballpark. “That’s the way it is; that’s what October means.”