Rodrigo Lopez (4-3) pitched an effective 5 1-3 innings, allowing two earned runs and the bullpen held on for Chicago. Wood's last save came on June 29, 2010 against Toronto while he was with Cleveland, but he had his club record tying streak of eight straight strikeouts dating back to Aug. 5 broken by Jason Michaels, who flew out to begin the ninth. Wood struck out the last two batters.
Henry Sosa (0-2) allowed four runs on seven hits with six strikeouts in six innings for Houston, which has dropped seven in a row and 10 of their last 11. He set down nine in a row at one point before Marlon Byrd walked with one out in the fourth.
Soto extended the Cubs' lead to 4-1 with a two-out two-run double in the sixth scoring Byrd and Reed Johnson, who had reached on back-to-back singles.
Pena gave the Cubs a 2-0 lead in the first with a two-run double off the hill in deep center that scored Darwin Barney, who had walked, and Ramirez, who had singled.
Martinez scored in the fourth to cut the lead to 2-1. After Martinez singled to start the inning, Downs knocked a one-out double to right. Tyler Colvin's throw to second to try to get Downs bounced off the base far enough for Martinez to score from third.
The Cubs got out of the inning as Brian Bogusevic flew out to Byrd, who fired an on-target throw to third to get Downs trying to advance.
Downs closed the gap to 4-3 with a two-run double in the sixth that scored Jose Altuve and Martinez and chased Lopez.
NOTES: Houston acquired 19-year-old OF Domingo Santana from Philadelphia as the player to be named later in the July 30th trade that sent OF Hunter Pence to the Phillies. Santana, who was ranked by Baseball America as the No. 9 prospect in the Phillies' organization, had been playing at Class A Lakewood for the Phillies, and has been assigned to the Astros' Class A Lexington team. Cubs recalled LHP Scott Maine from Triple A Iowa Monday to fill the empty roster left after RHP Carlos Zambrano was placed on the disqualified list Saturday. RHP Ryan Dempster (10-8) takes on RHP Brett Myers (3-12) Tuesday in the second game of the three-game series. Dempster is 6-3 with a 3.07 ERA in 12 starts since June 8, while Myers is looking to snap a career-long six game losing streak.