"Somebody's got more walk-off hits in the last two nights than I have in my whole career," Berkman said.
Blum delivered in the clutch once again for the Astros on Thursday, ripping a two-out single down the first-base line in the 13th inning to score Hunter Pence from second base and send the Astros to their second 2-1 win over the Cubs at Minute Maid Park in as many days.
"We did a good job of working walks and getting hits, and the more opportunities you have, the more opportunities you have to win a ballgame," said Blum, who singled home the winning run in the ninth inning Wednesday. "Our pitchers kept their opportunities to a minimum and did a good job."
The Astros have won eight of their past 11 games and went 7-3 during their 10-game homestand against Colorado, Pittsburgh and Chicago. Houston has won four consecutive series for the first time this season and finds itself only five games out of first place in the National League Central.
"That's great," Astros manager Cecil Cooper said. "That's what we were looking at coming [into the homestand]. We're playing real good baseball and that's what we have to do. For the most part, pitching is great and we've scratched out some wins. That's what it's about."
Houston' s pitching staff held the Cubs to six hits, with the bullpen limiting Chicago to three hits in the final 7 2/3 innings. The only run the Cubs scored came with one out in the ninth on a solo homer by Derrek Lee off closer LaTroy Hawkins that forced extra innings.
Jeff Fulchino (2-1) pitched the final three innings for his second career win.
"I knew we were shorthanded as a staff, so I knew me getting in that game meant I had the rest pretty much," Fulchino said. "It was a good team win. We had a real good homestand. As a staff, I think we did really well overall and had some clutch hitting, and that's what it's all about."
Astros right-hander Russ Ortiz, making his fifth start of the season and first since May 7, threw 5 1/3 innings to extend his scoreless-innings streak to 17 2/3, the longest such streak by an Astros pitcher this year. He tossed 4 1/3 scoreless innings in relief Sunday against Pittsburgh.
"I didn't fall behind too much and that allowed me to stay aggressive," said Ortiz, who also went 2-for-2 at the plate for his 17th career multihit game. "These guys are very good hitters and they have a lot of guys who have pop, so you have to make your pitches and that's all I've been trying to do lately."
Alberto Arias pitched 1 1/3 innings for his sixth consecutive scoreless outing, and Chris Sampson worked the eighth and hasn't allowed a run in 10 of his past 11 outings.
"They did outstanding," Ortiz said. "We talked awhile back that we needed to be solid in the bullpen and it was an all-out bullpen effort today. They threw the ball great and had great command in key situations. They gave the team opportunities to come back."
Astros center fielder Michael Bourn accounted for the game's first run when he doubled and scored on a Carlos Lee sacrifice fly in the first inning, and provided the game's biggest thrill in the seventh when he made a spectacular catch while falling down on Tal's Hill to rob Micah Hoffpauir of a 420-foot hit.
"I lost sight of it at the end but I knew where it was going to land," Bourn said. "I just put my glove to where it was going to be at and I caught it."
Ortiz left in the sixth with runners at first and second and one out. Tim Byrdak struck out Kosuke Fukudome, and Arias got Lee to ground out to second base to end the inning and the threat. The Cubs were 0-for-6 with runners in scoring position.
"That was pretty impressive," Berkman said. "Whenever you get in a situation like that you think they're definitely going to score one run, and it's just a matter of keeping them from scoring more than that. Very rarely do you get out of a situation like that, and they did a tremendous job."
Blum (3-for-6) became the first Astros player to have a game-winning hit in consecutive games since Derek Bell in 1996. The only other player to do it this season is the Dodgers' Andre Ethier, who accomplished it earlier this month against Philadelphia.
"It's great," Ortiz said. "It's not that often you get chances to win a ballgame late, and fortunately for us, he's come through. We needed to win this game and they had a great pitching performance, too, and it was one of those things where you have to scratch out a run, and we were able to do that. I'm happy. He's a great teammate and fun to play with."
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.