Capuano (3-0) held the Nationals to three hits and two walks over 6 2/3 innings, while striking out nine.
Josh Lindblom followed with 1 1/3 shutout frames and Kenley Jansen collected his second save despite allowing two walks in the ninth as the Dodgers swept a three game-set from the Nationals and improved to 16-6.
James Loney provided the game's only runs with a two-run single in the sixth inning.
Gio Gonzalez (2-1) absorbed the loss, surrendering two runs. While he gave up only three hits, the Washington left-hander was wild, issuing five walks to go with seven strikeouts over six innings.
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