Kerry Wood went eight innings and struck out 10, giving up three runs, two of them earned.
The Cubs' offense gave Wood an early lead, as Moises Alou hit a sacrifice fly to left, scoring Corey Patterson to give the Cubs an early 1-0 lead.
The Cubs would extend that lead in the third, as Alou again drove in Patterson, this time on a run-scoring double that extended the lead to 2-0.
The Cubs appeared to have two more runs in the fourth when catcher Michael Barrett sent a drive down the left field line that was originally signaled a two-run homerun. However, umpires later decided the drive was foul, thus reversing the call.
In the bottom of the inning, Jim Edmonds hit a double into left-center field that scored Albert Pujols and cut the lead to 2-1.
The Cardinals would even things up in the fifth on Reggie Sanders' eighth homerun of the season.
Then, in the sixth, former Cub Tony Womack reached on a single and then moved to third on a errant pickoff throw from Wood. Ray Lankford proceeded to hit a sacrifice fly, giving the Cards the lead, at 3-2.
The Cubs tied the game in the top of the seventh when Barrett scored on a wild pitch from Cardinal reliever Ray King. The 3-3 score would hold up until the bottom of the ninth when Pujols, Edmonds, and Edgar Renteria all walked to load the bases with one out in the ninth.
Cubs reliever LaTroy Hawkins came on and got Sanders to pop out to first baseman Derrek Lee for the second out, but misfired on a 3-2, payoff pitch to Matheny to give St. Louis the victory.
LHP Steve Kline (1-1) picked up the victory for the Cardinals. Kyle Farnsworth (0-1), who walked Pujols to lead off the ninth, was tagged with the loss.
The Cubs and Cardinals continue their four-game series tomorrow night at 6:15 CT. Matt Clement (3-1) will go to the mound for the Cubs against Jeff Suppan (2-2).
Walk-off: Cards Steal Victory from Cubs
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