ST. LOUIS -- The Cardinals celebrated a walk-off victory over the Chicago Cubs on Sunday night only to find out that they hadn't won the game.

The drama occurred in the bottom of the ninth with the score tied at 3 and Ryan Ludwick batting with the bases loaded and one out. Ludwick hit a grounder to second off Cubs reliever Esmailin Caridad and was called safe at first when Ryan Theriot's throw on a potential inning-ending double play pulled first baseman Derrek Lee off the bag.

Fireworks went off and the Cardinals ran onto the field to celebrate as Skip Schumaker crossed the plate, but second-base umpire Marty Foster quickly put his hands up and began motioning for the Cardinals to leave the field. Lost in the commotion, Foster had called interference on runner Matt Holliday at second base for an illegal slide. The call meant Ludwick was out at first and the game went into extra innings.

"Guys are coming out of the dugout and shaking hands and you think the game's over," said reliever Mitchell Boggs, who gave up a two-run homer in the 11th inning to Jake Fox as the Cubs salvaged the final game of the three-game set with a 6-3 win at Busch Stadium. "But that's baseball."

Video replays showed Holliday slid late and well to the right of the second-base bag when he attempted his slide, causing the poor throw from Theriot that the Cardinals thought had won them the game.

"I feel like you have to break up the double play there by any means necessary," Holliday said. "[The umpire] said I wasn't close enough to the base."

Said Ludwick: "I didn't see the play. I was getting down the line and was avoiding Derrek's tag and I missed the base, so I scuffled back to get to the base because I didn't feel him tag me, and I looked over to second and saw where they were calling me out for Matty getting a little too wide on the slide."

The controversial, game-changing call appeared to be the correct one by Foster, who immediately signaled for the Cardinals to stop celebrating and leave the field so that the game could continue.

"[Foster] called it right away," said Cubs manager Lou Piniella. "I wasn't watching the play at second base. I was watching the throw to first. I thought Derrek had touched the runner."

The Cardinals stood in disbelief as the Cubs slapped hands and celebrated as they left the field. Manager Tony La Russa hurried out to argue with Foster but the game continued.

"[Foster said that] Matt went out too far off the line to break it up," La Russa said. "I didn't see it, but he showed me the slide mark."

The momentum immediately swung to Chicago's dugout as the Cubs scored three runs in the 11th to avoid being swept by their division rivals. The Cardinals' magic number to clinch the NL Central remains at four and their division lead sits at 10 games.