Back-to-back homers vault Cubs over Nats

Back-to-back seventh-inning home runs by 3 victory game series.

Ryan Dempster (10-8) threw seven strong innings, allowing one run on three hits and two walks while striking out six in the Cubs' ninth win in 11 games.

Carlos Marmol worked out of a bases-loaded jam in the ninth to earn his 26th save of the year.

Jordan Zimmermann (7-10) allowed four runs on nine hits and two walks through 6 2/3 innings. He also struck out seven in Washington's fifth defeat in eight games.