Updated

Jeff Samardzija tossed seven outstanding innings as the Chicago Cubs knocked off the Houston Astros, 7-1, in the opener of a three-game series at Wrigley Field.

Samardzija (8-10) matched a career-high with 11 strikeouts and allowed just one run on four hits while walking three to snap a personal three-game winless streak.

"He's pitched in a lot of really tight ball games it seems like all year," Cubs manager Dale Sveum said. "Obviously that split showed up tonight and it was pretty devastating. His velocity was pretty good."

Darwin Barney and Alfonso Soriano each clubbed two-run home runs. Welington Castillo drove home a run and Anthony Rizzo added an RBI single among his four hits for the Cubs, who finally got in the win column after dropping 11 of their previous 12 games.

Brandon Barnes provided all the Astros offense with a pinch-hit home run in the club's seventh loss in nine tries.

Armando Galarraga (0-3) was saddled with the loss after giving up five runs on seven hits with two walks and a pair of strikeouts over five innings.

"There's no doubt he needed to throw more strikes. His stuff is good enough," Astros manager Brad Mills said. "When he got ahead of hitters, he needed to be able to make some better pitches."

The Cubs drew first blood in the second when Starlin Castro reached base with a single and Barney smoked a slider from Galarraga into the left-field seats for his sixth long ball of the season.

David DeJesus started the Cubs third with a walk but was erased on a fielder's choice by Josh Vitters, who stole second and later scored on a base hit back up the middle by Rizzo, widening the lead to 3-0.

Soriano extended the Cubs' lead to 5-0 in the fifth when he got a first-pitch slider from Galarraga and yanked it down the line in left and into the bleachers for his 21st homer of the season.

Barnes got the Astros on the board in the sixth when he led off the inning with a deep drive over the wall in left-center field, cutting the deficit to 5-1.

Soriano and Castro coaxed back-to-back two-out walks in the seventh and Castillo beat out an infield hit, scoring Soriano. Barney then scored on a Vitters sacrifice fly in the eighth to finish off the rout.

Game Notes

Prior to Monday's game, the Cubs selected the contract of pitcher Michael Bowden from Triple-A Iowa and optioned pitcher Brooks Raley to the minor league club. The team also transferred infielder Ian Stewart to the 60-day disabled list...The Cubs improved to 15-8 in their last 23 home games...Prior to the game, former Chicago Blackhawk Eddie Olczyk threw out the ceremonial first pitch...Astros outfielder Steve Pearce had his career-best eight-game hitting streak snapped...Houston fell to 11-47 on the road this season.