Game 1 Cardinals starter Adam Wainwright: “I think we have a 100-win club, I really do. But we definitely had some key injuries.” (Jeff Roberson/ASSOCIATED PRESS)

That the St. Louis Cardinals were in this position — in the National League Division Series, awaiting the Washington Nationals on Sunday — is a staggering accomplishment in itself. It’s strange that one could even say that about a defending World Series champion, but after losing longtime manager Tony La Russa, otherworldly slugger Albert Pujols and terrific pitching coach Dave Duncan, and having numerous injuries to major contributors throughout the season, thus was the case.

Despite all of the above, the Cardinals still have one of the sport’s best offenses and a strong starting rotation as they once again find themselves in the playoffs as the NL’s lowest seed, a team on a run with experience that opponents fear. Last season, they sneaked into the postseason on the final day and won a World Series. This year, they earned the second wild-card spot on the penultimate day of the season and finished six games behind the Atlanta Braves. They still managed to topple Atlanta, peaking at exactly the right time.

It’s as if there’s something inside these Cardinals that is awoken around this time of year. They find an utter focus that propels them through September and into the postseason.

“Given the fact of all the changes we went through this past offseason, to win 88 games, I certainly would have taken that,” Cardinals General Manager John Mozeliak said. “To look back and try to say, ‘Were we underachieving?’ I just don’t feel that. I feel this club played well enough to qualify and that’s the most important.”

Judging solely by the quality of their lineup and strong pitching, it seems as if the Cardinals are much better than their record suggests. During the regular season, their lineup produced the fifth-highest scoring offense in the majors (4.72 runs per game), rivaling the totals of American League teams, and a starting rotation that overcame several injuries to post the fourth-best ERA (3.62) in the majors.

They were talented and deep enough to deal with the loss of aging but experienced ace Chris Carpenter, the 2005 NL Cy Young Award winner who returned two weeks ago, and injuries to starters Jaime Garcia and Jake Westbrook. They could withstand the ups and downs of Adam Wainwright, a top right-handed starter who was pitching in his first full season back from Tommy John surgery.

On offense, they were without Pujols, a three-time MVP who left via free agency; Lance Berkman, a six-time all-star who played in only 32 games because of knee injuries; and everyday shortstop Rafael Furcal to an elbow injury in August. La Russa retired after 16 years managing the Cardinals, and Duncan, one of the best pitching coaches in baseball, took an absence to tend to his ailing wife.

“We didn’t play our best ball, no doubt,” said Wainwright, the Cardinals’ starter on Sunday. “I think we have a 100-win club, I really do. But we definitely had some key injuries. We lost Chris Carpenter, Lance Berkman, Rafael Furcal. We lost some key pieces along the way. Allen Craig missed a month. These are some big bats. To be in the postseason and go in and win a really tough game against Atlanta yesterday is nothing to hang our head about. We have accomplished something great.”

The Cardinals enter the opening game of the NLDS having won eight of their past 11 games, including taking two of three games from the Nationals at Busch Stadium Sept. 28-30. They may have the worst record of all the NL playoff teams, but they went 17-13 in September and October, good enough to put them in this position.

In Friday’s inaugural one-game NL wild-card matchup, the Cardinals fell behind early by two runs against young Braves ace Kris Medlen. They recovered calmly, took advantage of the Braves’ mistakes and took the lead in the fourth inning. They didn’t have the rushed, overly aggressive at-bats that plagued the younger, less experienced Braves hitters. They continued to capitalize on miscues, building a four-run lead in the seventh inning and working out of potentially harrowing jams.

“I don’t think you can say enough about what those guys went through in 2011,” Cardinals Manager Mike Matheny said, “what they overcame, how much they were the underdog and how they were ruled out and all those things that brought them together which defines the character of a team, and ultimately defines character of people. All of those are benefits that they have earned and they worked their way through, and this team is doing the same thing this year.”