Coming off a four-game sweep at Milwaukee that boosted their lead in the NL Central to five games, the Cubs stumbled against a team that just traded two of its best players
- outfielders Jason Bay and Xavier Nady.
Karstens (1-0), acquired in last week's deal that sent Nady to the New York Yankees, pitched six impressive innings in his first start of the season. Andy LaRoche, obtained from the Dodgers in the Manny Ramirez deal Thursday that moved Bay to Boston, singled and scored a run.
Right fielder Brandon Moss, who came from Boston in the Bay trade, started one of Pittsburgh's four double plays. The victory moved the Pirates out of last place.
Jason Michaels hit an RBI single during a two-run second, then hit a solo homer off Jason Marquis (6-7) in the sixth.
Jack Wilson added three hits and drove in the Pirates' other run. He just missed a homer after Michaels connected, winding up with a double when his drive to left hit the basket above the ivy and bounced onto the field.
That was enough for Karstens, who gave up five hits in his 10th career start. He was one of four players the Pirates got when they traded Nady and reliever Damaso Marte to the Yankees.
Denny Bautista, Sean Burnett and John Grabow combined for three hitless innings of relief. Grabow got his first save of the season.
The Cubs returned home following a sweep at Milwaukee in which they outscored the Brewers 31-11. Chicago plays 19 of 28 games at Wrigley Field this season, where they are now 39-15.
But the NL leaders in hitting and scoring stranded eight runners, leaving the bases loaded in the fourth.
The Cubs threatened again in the eighth when Bautista walked Kosuke Fukudome and Aramis Ramirez, but pinch-hitter Reed Johnson grounded into an inning-ending double play while batting for Jim Edmonds.
