Chicago, IL (Sports Network) - Jeff Karstens impressed in his Pirates debut, tossing six shutout innings as Pittsburgh topped the Chicago Cubs, 3-0, in the opener of a three-game series at Wrigley Field.

Karstens (1-0), acquired from the Yankees last week in the trade that sent Xavier Nady and Damaso Marte to New York, allowed just five hits and four walks while striking out two to earn his first win since September 22, 2007. John Grabow earned his first save of the season for the Pirates, winners in three of their last four overall.

"They haven't seen me and I haven't seen them so they really had no idea how I was going to attack them," Karstens said. "I know we threw a lot of off-speed stuff. They're a really good fastball-hitting team and sometimes that's what you got to do to win. I mean, I walked four guys but it didn't hurt me."

Jason Michaels homered and drove in two runs for Pittsburgh, while Jack Wilson went 3-for-4 with a run batted in. Andy LaRoche, picked up from Los Angeles on Wednesday as part of the trade that sent Jason Bay to Boston and Manny Ramirez to the Dodgers, was 1-for-4 and scored a run in his Pittsburgh debut.

Aramis Ramirez went 2-for-3 for the Cubs, who had a five-game win streak snapped, thanks largely to four double-play groundouts. Jason Marquis (6-7) lost after allowing three runs on eight hits in six frames, striking out two and walking one.

Pittsburgh picked up two runs in the second inning and never looked back. Ryan Doumit was hit by a pitch to start the inning, and LaRoche followed with an infield single in his first at-bat with the Pirates. One out later, Michaels grounded a single to right to plate Doumit, and Wilson followed by punching an RBI single of his own to right.

The Cubs threatened with two outs in the fourth when a single by Ramirez sandwiched between walks to Derrek Lee and Jim Edmonds loaded the bases, but Karstens escaped the jam when Geovany Soto flew out to center.

"He threw the ball well," Ramirez said of Karstens. "One team has a disadvantage, nobody faced him before. He changed speeds well. Good changeup, good breaking ball."

Michaels extended the lead in the sixth with a two-out solo blast, ripping a first-pitch fastball over the wall in left. Wilson then launched a fly ball to deep left that ticked off the yellow line on the netting atop the wall for a double, but he was stranded there.

The Pirates relief corps benefited from double plays in the eighth and ninth to seal the win. Denny Bautista walked Kosuke Fukudome and Ramirez in the eighth before being lifted for Sean Burnett, who induced pinch-hitter Reed Johnson into a 4-6-3 double play.

Grabow issued a one-out walk to Mark DeRosa in the ninth, but pinch-hitter Henry Blanco bounced into a 5-4-3 twin-killing to end the game.