Leadoff hitter Starling Marte singled and scored in each of the first two innings as Pittsburgh built an early 4-0 lead. The Pirates moved a season-best 11 games over .500 with its 11th victory in 13 games.
Edwin Jackson (1-7) gave up two runs in the first inning and two more in the second. He lasted only three innings and has a 6.11 ERA through 10 starts.
Jackson is in his first season with the Cubs after signing a four-year, $52-million contract over the winter as a free agent.
