WASHINGTON -- Brad Hawpe has become an energy source for a Rockies club that badly needs it.

Hawpe's two-run homer in the fifth inning broke a tie and lifted the Rockies to a 4-3 victory over the Nationals at Nationals Park on Friday night before 27,965 fans.

Hawpe, who has 20 homers this season, also hit the game-winning homer in the Rockies' previous victory, over the Diamondbacks on Wednesday at Coors Field. Hawpe, whose homer followed Matt Holliday's RBI double off Tim Redding (8-8), also has hit .396 with three home runs in the Rockies' last 13 road games.

Friday's victory began a six-game road trip for the Rockies, who are trying to erase a 3-7 homestand. The Nationals have lost eight straight since sweeping a doubleheader over the Rockies at Coors on Aug. 7.

Troy Tulowitzki also homered for the Rockies, with a solo shot off Redding in the third to tie the game at 1. It was Tulowitzki's first homer since July 2 against the Padres. He had 92 at-bats and a disabled-list stint for a lacerated hand between homers.

Rockies starter Jorge De La Rosa (6-6) gave up six hits and walked three in six innings, but also struck out seven and held the Nationals to three runs. Manuel Corpas and Taylor Buchholz threw scoreless seventh and eighth innings, and Brian Fuentes earned his 23rd save.