"Big games usually bring out the best in Pirates left-hander Zach Duke.

Tuesday night, Duke was matched up against Philadelphia Phillies ace Roy Halladay. Duke was winless in his previous seven starts. Halladay already seems on course for another Cy Young-caliber season.

"It's a challenge," Duke said. "You know the margin for error is very small and it's going to be a battle. It makes you focus that much more."

Duke rose to the occasion, and the Pirates generated just enough offense to slip away with a 2-1 victory.

"Anytime you get a quality win like that, it's a big morale boost," Duke said.

It snapped the Pirates' six-game losing skid at Citizens Bank Park. By going 3-2 against the Phillies and Chicago Cubs, the Pirates notched their first winning road trip since August 2007.

It also was the first victory in five decisions for Duke (3-4). The left-hander went six innings and allowed one run and six hits. He struck out five and walked two.

"You've got to tip your cap to our bullpen and Zach Duke," said Garrett Jones, who drove in the winning run with a sixth-inning single. "To hold that lineup to only one run is a pretty special thing."

Relievers Evan Meek and Joel Hanrahan each threw a scoreless inning. Octavio Dotel worked a 1-2-3 ninth for his eighth save.

"Zach pitched well," Phillies outfielder Shane Victorino said. "Sometimes, he's going to be like that. He's that good. He kept our hitters off balance. Other than (the fifth) inning, we never really had any momentum."

Credit the defense, too. In the fifth, center fielder Andrew McCutchen threw out Jayson Werth at the plate ? McCutchen's team-leading fourth outfield assist. The Pirates lead the majors with 13 outfield assists."