ST. LOUIS -- When you're up against Cy Young candidate Brandon Webb, outstanding baserunning is a necessity.

The Cardinals came up short in that department and short on the scoreboard Monday night in a 4-2 loss to the Diamondbacks at Busch Stadium. St. Louis outhit Arizona 11-10 and had chances to start the final homestand on a high note, but instead retreated to their clubhouse mulling what might have been.

Three big baserunning plays in particular left the Cardinals feeling the frustration. Felipe Lopez was picked off first when the Cardinals had a chance to put a crooked number on the board in the first. Troy Glaus was doubled off second when he represented the tying run in the eighth. Third-base coach Jose Oquendo stopped Cesar Izturis at third on a Lopez single to center in the seventh that looked like it might tie the game.

It was that kind of slip-and-slide night for the Cardinals, who now face a magic number of one for elimination in the National League Wild Card race. One Mets victory or one Cardinals defeat will officially eliminate St. Louis from postseason contention.

"We came so close so many times," manager Tony La Russa said. "It was really a frustrating loss."

Webb, who is now 22-7, was given a 1-0 lead in the first on Conor Jackson's RBI double. The Cardinals bounced right back in their half of the inning when Skip Schumaker and Lopez singled to set up a first-and-third situation with Albert Pujols coming up.

But just when it looked like a big inning might be in the making, Lopez was picked off first. The Cardinals did eventually score one in the inning when Webb was charged with a balk trying to pick off Pujols at first. Lopez felt a balk should have been called on his pickoff play, too.

"They were able to catch it the second time," Lopez said.

St. Louis starter Todd Wellemeyer pitched well overall, but didn't have the answers for leadoff man Stephen Drew. In the midst of a 3-for-4 night, Drew had a run-scoring double in the fourth and a solo homer in the sixth that put the D-backs up, 3-1.

The Cardinals made one more run at Webb, getting singles by Adam Kennedy and Izturis and an RBI groundout by Schumaker to reduce the margin to 3-2. With Izturis at second, Lopez singled up the middle, and Oquendo held up Izturis at third as center fielder Chris Young came up throwing.

"There isn't a better third-base coach in baseball than Jose," La Russa said. "He's right there with the best of them. He read what he read. The center fielder has good speed and a good arm. The ball was hit like a bullet. If he had been thrown out at the plate and Albert is coming up, we would have all said, 'What are you doing?'"

Webb was out of the game after throwing 121 pitches in seven innings. Reliever Brandon Lyon was greeted with a Ryan Ludwick single and a Glaus double that put the tying runs in scoring position. Aaron Miles then hit a liner to second, and Glaus was doubled off.

"He's upset; it's not good baserunning," La Russa said. "Miles is trying to hit the ball to the right side, so [Glaus] wants to make sure he gets to third base."

With Monday's loss, the Cardinals fell to 80-76 overall and 6-13 in September.

"It's tough," Miles said. "We're competing out there every day. We're not getting the breaks to go our way. But we've got to fight. We've got to turn the page and try to finish this thing on a good note."

The Diamondbacks (79-77) are now two games back of the Dodgers in the NL West. While Arizona is still clinging to hopes of a division title, the Cardinals just want to reverse their September doldrums.

"I'd love to win these next six games to make our record look a little better," Wellemeyer said. "We played so well for five months."