The Cubs picked up their offense against the Nationals Saturday, and Ryan Dempster picked up his 15 win.
Dempster, who converted from a closer to a starter this season is leading the team in wins.
He gave up one run over 7 1/3 innings while striking out four. Dempster is a remarkable 12-2 at home this season.
Aramis Ramirez also contributed greatly to the Cubs win driving in six runs on two three run homers.
In the first three innings the Cubs stranded eight base runners including leaving the bases loaded in the first.
The Cubs will look for their eighth straight series victory on Sunday when they send Rich Harden to the mound to face Jason Bergmann.