The Cubs ventured into familiar territory Tuesday night at Wrigley Field in a crazy 7-5 victory over Houston.

"It was weird as heck out there," manager Dusty Baker said. "It had a 'Twilight Zone' feel."

The Cubs gave away a run when left fielder Moises Alou lost a ball in the ivy in the fourth inning, but got two back the easy way when the Astros' Craig Biggio dropped a fly ball off Alou's bat in the seventh.

With the game tied 5-5 with two outs in the seventh, Biggio, playing left field since the Astros obtained Carlos Beltran, let Alou's fly glance off his glove, allowing two runs to score.

Kyle Farnsworth and LaTroy Hawkins nailed down the victory, moving the Cubs to within 3½ games of first-place St. Louis in the National League Central.

Astros left-hander Andy Pettitte carried a 4-1 lead into the fourth, but Corey Patterson's two-run homer pulled the Cubs to within a run, and Aramis Ramirez tied it with a solo shot off Kirk Bullinger in the sixth.

Carlos Beltran slammed a Francis Beltran fastball onto Sheffield Avenue in the seventh to put the Astros on top again before the Cubs scored three in the seventh on an RBI single by Mark Grudzielanek and Biggio's two-run error.

When baseball legend Bill Veeck helped plant the ivy on the outfield wall at Wrigley Field in September 1937, he surely must have known of the consequences of his beautification project. Sixty-seven years later, outfielders are still unsure of what to do when a ball enters the vines, including veterans like Alou who play there every day.

Alou tried a new version of the hidden-ball routine Tuesday, and it cost the Cubs an early run. The Cubs trailed 2-1 in the fourth when Adam Everett doubled to left to score Morgan Ensberg from third. Alou scooped it up on a bounce off the wall, but the ball flipped back into the ivy. Though replays showed the ball was partially visible at the foot of the wall, Alou held up his hands as though he couldn't locate it, hoping a ground-rule double would be called.

But Alou's schtick didn't work on Gene Lamont, the Astros' third-base coach, who fully understood the ground rules and frantically waved Everett home as Alou began sorting through the vines in search of the missing ball.

"I saw it and I knew I had no chance, so I kicked it in the ivy," Alou said. "The umpire saw it, and they gave him [the run]. I don't know any rules. That's why I can't manage when I retire."

Everett scored without a play and plate umpire Dana DeMuth quickly made it official. The play was scored a double and two-base error on Alou.

"If you're around this game long enough, you'll see something you've never seen before," Baker said.

A similar incident occurred at Wrigley on April 19 when Ramirez hit a shot that rolled into the vines in left but stopped at the base of the wall. Like Alou, Cincinnati left fielder Adam Dunn held his hands up, believing it was a ground-rule double. But since it was only April, the vines were still bare and the ball was clearly visible. The umpires waved it off and Ramirez wound up with a triple.

"If you can see it," umpiring supervisor Marty Springstead said that day, "you can dig it out."

On June 5, 1998, when a Magglio Ordonez shot got lost in the vines, taking a White Sox run off the board in a 6-5 loss, former Cubs pitcher Terry Mulholland facetiously theorized a squirrel hung onto the ball to save the Cubs. The play was seen as an indication the Cubs luck finally had changed.

"Last year, the squirrel would've bit somebody," Mulholland said.

Six years later, the ivy remains a mysterious place for both friend and foe.