• Unsung hero: Houston pitchers held Chicago scoreless after giving up a three-run bomb to Mark DeRosa in the third.
• Figure this: The Cubs stranded 15 runners, including leaving the bases loaded in the 11th.
• Quotable: "We had some opportunities and didn't get it done. That's a tough one to swallow." -- Cubs first baseman Derrek Lee
• Hunt for October: Chicago fell one game behind Milwaukee and the NL Central lead as the Brewers topped the Pirates 6-1.
-- ESPN.com news services
Astros 5, Cubs 4 (11 innings)
HOUSTON (AP) -- The Chicago Cubs know they can't waste too many more chances like this.
Chicago blew a 4-1 lead, stranded 15 runners and squandered a bases-loaded threat in the 11th. The Cubs have lost four of six and fell one game behind Milwaukee, which beat Pittsburgh 6-1.
"We had some opportunities and didn't get it done," Cubs first baseman Derrek Lee said. "That's a tough one to swallow."
The Astros ended a five-game losing streak and won for the fifth time in 13 games since Cecil Cooper replaced Phil Garner as manager on Aug. 27.
"We continue to play hard, that's all you can ask," Cooper said.
"I made a stupid pitch," Dempster said, without waiting for reporters to ask him a question. "I walked a guy, made a stupid pitch and lost the game."
With that, Dempster finished buttoning his shirt and left the clubhouse.
Unless they win the rest of their games, the Astros will finish with a losing record for just the second time since 1991.
"Any time you can win a game in extra innings, it's good, no matter where you are," Scott said. "We want to finish strong. We haven't lived up to expectations and we know it."
Mark DeRosa hit a three-run homer for the Cubs, who dropped to 2-8 in extra-inning games this season. Chicago has lost seven of 13 meetings with Houston.
"We're still in it," Derrek Lee said. "You've got to turn the page, come back and try to get them tomorrow."
The Cubs put two runners on with one out in both the eighth and ninth innings. Carlos Lee made a diving catch in left-center on Ryan Theriot's liner to end the first threat and DeRosa grounded into a double play to stall the second.
"We had some chances, we left some runners out there," Derrek Lee said. "They made some great defensive plays. We just didn't get it done."
Chicago reliever Bob Howry retired the six batters he faced in the eighth and ninth -- striking out four -- to force extra innings. Chicago's bullpen retired 13 straight Astros before Loretta walked in the 11th.
"These are big games for us," Howry said. "You'd love to be out and have a five- or seven-game lead and have a little leeway. We don't, but we've got guys who know what it takes to win. Now, we've just got to come out and do it."
The Cubs took a 1-0 lead in the second when Jones singled and scored on Jason Kendall's double.
Scott singled in the second and moved up on a grounder and Jason Marquis' wild pitch. When another pitch skipped past Kendall -- this one was ruled a passed ball -- Scott scored to tie the game.
Backe, making his second start since a yearlong recovery from Tommy John surgery, retired the Cubs in order for the first time in the fifth inning. Humberto Quintero doubled in the Houston fifth, Jason Lane pinch-hit for Backe and singled, then lined a two-run triple to cut Chicago's lead to 4-3.
Carlos Lee led off the sixth with a single and Loretta hit a tying double.
Craig Biggio hit his 666th double in the first inning, passing George Brett and moving into fifth place all-time. Biggio has more doubles than any right-handed hitter in history. ... Alfonso Soriano, the Cubs left fielder, dropped Biggio's routine fly with one out in the third inning. He recovered in time to throw to second and force out Pence. ... Pence set a Houston rookie record with his 51st extra-base hit of the season. ... The Cubs have lost four in a row at Minute Maid Park for the first time since the ballpark opened in 2000.