CHICAGO -- Thomas Diamond received a game ball and a beer shower after his first major league win.
"It's always nice to get the first. I wish it would have happened a little sooner," Diamond said. "Now, hopefully we can go on and win a few more."
Kosuke Fukudome had three hits, including a go-ahead double, during a perfect day at the plate for the Cubs. Carlos Marmol escaped a bases-loaded jam in the eighth inning and finished for his 25th save in 30 chances.
Gorzelanny was knocked out in the third when Jose Tabata lined a shot off his right hand. The left-hander, a former Pirate who is a native of nearby Evergreen Park, Ill., departed for X-rays.
"That was very scary," Tabata said. "I saw the ball and I thought it was his face. In the moment I froze. I hope he's better. I feel bad for that."
After Gorzelanny left, five Cubs relievers combined to allow four hits the rest of the way.
"Now that I've moved from the rotation to the bullpen, hopefully I can find a spot there and contribute," the 27-year-old Diamond said.
Diamond (1-3) gave up two runs and two hits in 1 2/3 innings. Marmol walked in a run with two outs in the eighth but struck out Tabata to preserve a 5-3 lead.
James McDonald (2-5) took the loss, allowing three runs and eight hits in five innings.
"For most of the game he wasn't able to get the ball down like he usually does and it cost him a little bit," Pirates manager John Russell said.
Diamond, called up from Triple-A Iowa on Aug. 2, struck out three and walked one. The Cubs won two of three in the series and finished 5-10 against last-place Pittsburgh this season.
"I've been feeling pretty good and I've been working on a new pitch -- a cutter -- with (pitching coach) Larry (Rothschild)," Diamond said. "Today I had a little trouble with it, but it's only about a week and a half old."
Fukudome finished 3 for 3 with two doubles and a walk. He also scored twice.
The Pirates chased Diamond in the fifth when leadoff batter Andrew McCutchen doubled home McDonald to trim the Cubs' lead to 3-2.
In the eighth, the Pirates had runners on first and second with two outs when Marmol entered. He walked pinch-hitter Delwyn Young and forced in a run with a walk to McCutchen before getting out of the inning.
"Command can be an issue (with Marmol)," Cubs interim manager Mike Quade said. "But I don't care. He got through it. He did a great job."
Pittsburgh recalled outfielder John Bowker, one of two players acquired in a late July trade with the Los Angeles Dodgers for reliever Octavio Dotel. ... The Pirates will swap starting pitchers this weekend against Washington. LHP Paul Maholm (7-13) will go Saturday instead of Sunday, with RHP Charlie Morton (1-10) pitching Sunday. ... Before the game, the Cubs rededicated a statue of late broadcaster Harry Caray outside Wrigley Field. Caray's wife, Dutchie Caray, was among those on hand for the ceremony.