HOUSTON -- The fortunes of the Astros and the chances of Henry Sosa picking up his first Major League win were decided by one pitch Monday night -- a 3-1 slider thrown to Cubs catcher Geovany Soto in the sixth inning that caught too much of the plate.
Carlos Pena laced a two-run double in the first inning and Soto added the kill shot with a two-run double in the sixth to send the Cubs to a 4-3 win at Minute Maid Park that extended the Astros' season-long losing streak to seven games.
"I tried to do the best I can, but it didn't work," said Sosa, who was making his second Major League start and first at home since the Astros called him up from Triple-A Oklahoma City last week.
Houston, which managed only one run in getting swept by the Dodgers over the weekend in Los Angeles, made the most of its five hits by pushing across three runs. J.D. Martinez (2-for-3) and Matt Downs (2-for-4 with two doubles and two RBIs) accounted for most of the damage.
"Everybody knows we're young and we didn't score but one run over in L.A.," Downs said. "Teams go through slumps like that where they don't score runs, but we're still learning."
Just like in his first Major League start last week in Arizona, Sosa overcame a rough first inning before settling down and giving the Astros a chance to win. He allowed seven hits and four runs while striking out six batters in six innings.
"He gave up those first inning runs, but came back and really threw the ball extremely well," Astros manager Brad Mills said.
The Astros' bullpen followed Sosa by allowing four hits in three scoreless innings. Houston relievers have given up two earned runs in the last 9 2/3 innings since getting touched for five runs in a two-inning span in Thursday's loss in Arizona. Sosa blew away Starlin Castro to start the game before allowing three consecutive baserunners to reach with one out in the first inning, culminating Pena's two-run double that a meandering Jason Bourgeois nearly tracked down on Tal's Hill in center field.
"He came out to Castro in the first inning and threw some really good sliders," Cubs manager Mike Quade said. "He got him out fairly easily. We weren't sure he was going to locate like that all night. Like a lot of young guys, he's got good stuff and is in and out command-wise, probably. Young pitchers are going to make some mistakes. He looks like a nice guy for the future for them."
Downs helped the Astros get a run back in the fourth when he doubled down the right-field line with one out in the fourth. J.D. Martinez advanced from first to third on the hit. An errant throw by right fielder Tyler Colvin allowed Martinez to score, cutting the Cubs' lead to 2-1.
A two-out, two-run double in the sixth inning by Soto put the Cubs ahead, 4-1.
"He got a 3-1 slider that backed up on him and got over the plate that Sosa was able to get in the sixth," Mills said. "Turned out to be a huge hit for them."
Jose Altuve reached on an error by Castro to start the sixth, and Martinez followed by drawing a walk. After Carlos Lee popped out, Downs hit a double into the left-center field gap that scored both runners easily, pulling the Astros within a run at 4-3.
"I went in a bad slump [0-for-24] about two weeks ago and came out of it four of five days ago and felt good ever since," Downs said.
Cubs starter Rodrigo Lopez (4-3) allowed five hits and three walks in 5 1/3 innings to get the win, and Kerry Wood pitched a scoreless ninth for his first save since June 29, 2010.
The Cubs have won four straight games against the Astros, who slipped further into last place.
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.