On the South Side of Chicago on Friday, his complete-game performance -- one in which he allowed just two runs -- was backed by no offense and ended in a loss. On Wednesday, he pitched well enough to beat Chicago's other team, only to watch the offense sputter early and the bullpen crumble late.
As soon as Duke exited, the Cubs pushed three runs across to break open a tie game, sending the Pirates to a 5-2 loss in front of 38,314 at Wrigley Field. With the loss, the Pirates ended their longest road trip of the season with a 5-5 record, but with just one win at each Chicago ballpark.
Before Chicago tagged Jesse Chavez and Sean Burnett for the win, though, they were stymied by Duke. Yet, the Pirates lefty has nothing but an 0-1 record to show for allowing only four runs in 15 innings in Chicago.
"Two games on this road trip that he should have won," manager John Russell said. "He's been very consistent. I think you see a lot of confidence in Zach. He really believes in what he's doing."
Duke's only troublesome inning was the first, when he fell behind five of six hitters. Milton Bradley drove in his fifth run of the series with a one-out triple. Duke then walked Derrek Lee.
He rebounded to get the ground ball that he wanted, but instead of an inning-ending double play, second baseman Delwyn Young made a throw low and wide of first that allowed the runner to reach safely and Bradley to score the inning's second run.
"It just slipped," said Young, who also went 0-for-4 at the plate in a spot start for Freddy Sanchez. "It was my mistake."
The run would count as an earned run against Duke because two outs cannot be assumed on a double play. Still, a good throw there would have had outfielder Reed Johnson out easily.
Chicago would get nothing more off Duke, who scattered five singles and one double over the next six innings.
"After that [inning] I kind of stepped back and said, 'I have to get ahead, get the counts back in my favor,'" Duke said. "After that I was able to move the ball around very well."
Other than not having the wins to show for it -- Duke's record stands at 5-4 -- Duke has done nothing but be a consistent and efficient presence on the mound all season. Armed with confidence and the stuff to back it up, Duke has now pitched at least seven innings in seven of his 10 starts this year.
He only accomplished that nine times in his 31 starts a year ago.
"I'm in a very good groove," Duke said. "My mind is very clear on the mound, and it just feels very good to be performing the way that I am."
After throwing 105 pitches, Duke left with the game tied. The Pirates had scratched back for one off Cubs starter Carlos Zambrano in the fourth on Ramon Vazquez's two-out double before Nyjer Morgan's speed in the seventh evened the game at 2.
Morgan led off the seventh with what looked to be a harmless single until left fielder Alfonso Soriano inexplicably missed picking up the ball. The ball then kept rolling, and Morgan, who ran hard out of the batter's box, kept running, all the way to third.
"I just kind of went out there and tried to get something going," Morgan said.
Zambrano rebounded to get Young to pop out, but when Zambrano's 0-1 pitch to Nate McLouth got past catcher Geovany Soto, Morgan took off immediately.
"I read the ball in the dirt, and it was just basically an instinct play right there," Morgan said. "I just reacted and went."
It was a bang-bang play with Zambrano and Morgan at the plate, but Morgan's left hand touched home just before Zambrano applied the tag. Zambrano, livid at the call, immediately voiced his displeasure to home-plate umpire Mark Carlson. Seconds later, the two made contact and Zambrano, never hesitant to be animated, was tossed from the game, making quite the scene in the process.
"I was safe," Morgan said afterward. "I was in there way before the ball got there."
From there, Russell turned to the right-handed Chavez, owner of a 1.83 ERA in 22 appearances this year. His string of seven straight scoreless appearances would be snapped, though, when, with one out, Johnson made Chavez pay for a 1-1 changeup left out over the plate.
"That's one of his better pitches," Russell said. "He just didn't get it down."
The ball landed in the left-field seats to give the Cubs a 3-2 advantage.
"It didn't change," Chavez said of the pitch. "It will be a tough one to swallow, especially how Zach kept us in the game. My job is to come in and keep the score tied so that our bats have a chance to get going."
Chavez then gave up a single before the Cubs' two doubles off Sean Burnett provided the three-run cushion.
The Pirates ran themselves out of a chance to piece together a comeback attempt in the ninth. After drawing a pinch-hit walk to start the inning, Freddy Sanchez inexplicably kept running to third on Morgan's fly-ball out to deep right. Sanchez was easily doubled off first.
The mistake loomed even larger when Young then followed with a walk. Had Sanchez not been erased off the basepaths, McLouth would have come to the plate as the potential tying run.
The Pirates' offense missed opportunities earlier as well. It went just 2-for-10 with runners in scoring position. In both the second and fifth, Pittsburgh put its first two runners on base only to watch both innings end without a run scored.
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.