The Tigers had been in a form slump, enduring 13 losing seasons including a 119-loss campaign in 2003, but have come out of the gloom to reach the World Series for the first time since 1984.
"We never had a chance in anybody's mind but ours," Tigers third baseman Brandon Inge said.
"We've come too far to stop now. You don't come this far to be second best."
The Cardinals scraped into the post-season with the worst win/loss record of any playoff team after a string of losses late in the season almost cost them a berth.
"We never gave up. We always believed in ourselves," Cardinals pitcher Jeff Suppan said.
St Louis managed to outlast the New York Mets to win the best of seven National League Championship 4-3, and reach the playoffs for the second time in three years.
"We're still the underdog," Cardinals slugger Albert Pujols said.
"They can hit. They can flat out hit."
Detroit can indeed hit, with shortstop Carlos Guillen batting .320 with 19 home runs, 20 stolen bases and 85 runs batted in (RBI) while outfielder Magglio Ordonez is averaging .298 with 24 homers and 104 RBI.
Fellow Tigers outfielder Craig Monroe hit a team-high 28 homers while third baseman Brandon Inge added 27 and leadoff man Curtis Granderson struck 19, while designated hitter Sean Casey returns after nursing a calf injury
Justin Verlander, rookie right-handed pitcher, will start game one for the Tigers after going 17-9 this season, with veteran southpaw Kenny "The Gambler" Rogers, to open on the mound for game two on Sunday.
Left-hander Nate Robertson gets the start on Tuesday in game three in St Louis, while Jeremy Bonderman will start game four.
Reyes to start for Cards
Meanwhile, the Cardinals have had minimal rest after their seven matches against the Mets, and coach Tony La Russa will use rookie Anthony Reyes as the starter in Saturday's opener.
Cardinals slugger Albert Pujols
practices ahead of the World Series
"He's next in line," La Russa said.
"It's a tough turnaround for us, but so much of this game is mental and the teams that make the World Series have to be mentally strong."
Jeff Weaver will start game two for St Louis, and he will be followed by reigning National League Cy Young Award winner Cris Carpenter in game three and Jeff Suppan, Most Valuable Player of the National League playoffs in game four.
The World Series sees a mate against mate match up, as St Louis first baseman Pujols, who hit 49 homers and 137 RBI, is the godfather of Tigers' second baseman Placido Polanco's children.
The Tigers beat the Cardinals in their only World Series encounter in 1968, and also defeated San Diego in 1984 for their fourth title in their past five appearances, while St. Louis last won the World Series in 1982 but lost in 1985, 1987 and 2004.
Detroit swept a three-game regular-season series between the clubs in June and are favourites to hand the Cardinals their fourth consecutive World Series defeat.