CHICAGO (AP) -- Two of their best players got traded. Their opponent was on a roll.
This looked like a bad time for the new-look Pirates to visit Wrigley Field.
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.
"They haven't seen me and I haven't seen them so they really had no idea how I was going to attack them," said Karstens, who gave up five hits. "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."
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.
"It was nice energy to see those guys," manager John Russell said. "You can tell they're excited to be here and also they have an idea of what they're doing."
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 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.
"It's hard because those are three really important players on this team," Michaels said.
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.
Was it a letdown for Chicago?
"You can say that, but I think you have to give their pitcher credit for once," Edmonds said. "I mean, he pitched a great game. We haven't seen him and we didn't have a lot of footage. And from what we saw he was definitely better than what we saw on video. I can't say 100 percent that we didn't have a letdown, but you definitely have to give that kid credit. It would be a shame not to give him the credit that he deserves."
While Karstens contained the Cubs, Marquis fell to 0-4 in six starts since beating the crosstown White Sox on June 21. He gave up RBI singles to Michaels and Wilson in the second.
Before the game, Pirates center fielder Nate McLouth talked about the departures of Bay and Nady.
"They were good presences in the clubhouse," McLouth said. "Their professionalism was something I learned from over the past couple years. It's something a lot of people will have to carry on."
Russell isn't sure when 1B Adam LaRoche will return from a a rib cage injury. When he comes off the disabled list, he'll be united with brother Andy. "There's no timetable," Russell said. "We're not going to rush. I know now he's very excited his brother's here." ... Russell said Andy LaRoche will be the regular 3B for now over Jose Bautista. ... Although Moss started in right field, he will be used mostly in left. ... Cubs RHP Jon Lieber, on the DL with a strained right foot, threw on the side on Friday and will "pitch three innings somewhere in the next few days," manager Lou Piniella said. ... Cubs rookie Jeff Samardzija struck out two in a scoreless eighth.