Nationals third baseman Ryan Zimmerman reached 19 games in his current hitting streak with a monster solo shot out of Wrigley Field in the first inning off of the Cubs' Ryan Dempster.
It is the second longest hit streak of Zimmerman's career, the homer coming on a slider from Dempster, who has allowed 16 homers this season.
The Nationals are looking to win their first road series under Davey Johnson and lead the season series with Chicago, 4-2.
Nationals starter Jordan Zimmermann has allowed just one hit through two innings.
Nationals lead 1-0 early on.