Aramis Ramirez got back to doing what he does best: driving in big runs to help the Cubs win.Ramirez, the team’s most reliable hitter since arriving seven years ago, snapped out of the worst slump of his career with a two-run, 11th-inning homer Monday night. His first home run since April 15 lifted the Cubs to a 4-2 victory over the Colorado Rockies.Ramirez, who has four homers, also drove in a first-inning run. The season-high three RBI give him 20 this season. He averaged 32 homers and 105 RBI from 2004-08 before being limited by injuries last season. He’s batting .175 — well below his .300 average as a Cub going into this year.His troubles as the cleanup hitter have been a big part of the Northsiders 17-22 start.Asked if he was relieved to deliver the Cubs’ first game-ending homer this year, Ramirez said: “No, I’m still hitting .170. I’ve got to get hits and drive in runs and just help this team. We need runs, and I’m one of the key guys.” Starlin Castro opened the 11th with his third hit of the game, a single off Matt Belisle (1-1). After Derrek Lee lined out, Ramirez lined a 1-0 pitch through a stiff wind into the left-field bleachers.While the Cubs won for only the fourth time in their last 13 games, the Rockies had a three-game winning streak snapped.Sean Marshall (3-1), the fourth Cubs pitcher, worked two perfect innings, striking out four.Cubs starter Randy Wells allowed one run on seven hits in 6 2/3 innings, but the bullpen couldn’t protect a late 2-1 lead.John Grabow opened the eighth by allowing Seth Smith’s single and walking Brad Hawpe. After center fielder Marlon Byrd made a diving catch on Troy Tulowitzki’s sinking liner, Grabow walked Todd Helton to load the bases.Carlos Marmol, unable to convert his first five-out save this season, walked Miguel Olivo on four pitches to force in the tying run before getting Ian Stewart to ground into a double play. Marmol then struck out the side in the ninth.Colorado starter Aaron Cook allowed two runs — one earned — on seven hits in seven innings. He came in with an 8.84 road ERA and still hasn’t won away from Coors Field since last July.Colorado tied it at 1 in the third as Carlos Gonzalez doubled with two outs, extending his hitting streak to 11 games, and Smith followed with a single.After shortstop Tulowitzki’s error on Mike Fontenot’s grounder kept the fourth inning alive, Koyie Hill snapped an 0-for-12 skid with an RBI single.

NOTES—Lou Piniella said Carlos Zambrano would be “stretched out” so he can be switched from short to long relief. Zambrano, a $91.5 million former All-Star, already had gone from the rotation to the bullpen. Piniella refused to say the Cubs were getting Zambrano ready to return to the rotation, but Zambrano told reporters he believes he’ll be a starter again……Rockies closer Huston Street strained his groin during a rehab appearance at Double-A Tulsa on Saturday. Street, who had 35 saves last year, has been on the DL all this season with right shoulder inflammation. Colorado hoped to have him back next week….Lee struck out twice and grounded into two double plays.