Enrique Hernandez's two-out single in the top of the 10th inning gave the Dodgers the lead. Keibert Ruiz tied it with a single in the bottom of the inning.
Lane Thomas hit a two-run home run and finished with three runs batted in for the Nationals. Andres Machado (4-1) was the winning pitcher with a shutout inning in relief.
The Nationals (64-78), who loaded the bases with one out in the bottom of the ninth and didn't score, won for only the second time in eight games on a nine-game homestand that wraps up Sunday.
The game began after more than a four-hour weather delay. This came after the teams waited through a long seventh-inning rain delay Friday night.
Max Muncy had a two-run homer in the eighth inning to go with an earlier sacrifice fly for the Dodgers (86-55), who were aiming for their third victory in a row. J.D. Martinez, in his second game since coming off the injury list, was 3-for-4 for Los Angeles.
Nationals starter Jake Irvin has gone eight consecutive appearances without a decision. He allowed a run on three hits and two walks while striking out four.
The Dodgers tied the game in the ninth off Nationals closer Kyle Finnegan on Kolten Wong's one-out single. James Outman reached on a one-out walk, stole second base and went to third on catcher Ruiz's throwing error.
Los Angeles rookie starter Bobby Miller gave up five runs in seven innings.
CJ Abrams had two of Washington's eight hits.
Luis Garcia's run-scoring single and Dominic Smith's sacrifice fly pushed Washington to a 3-1 lead in the fifth.
Hernandez lofted a sacrifice fly for the Dodgers in the seventh inning, but Thomas countered with a two-run shot with two outs in the bottom of the inning. Thomas has 24 home runs.
Muncy's 34th homer came with two outs in the eighth off reliever Hunter Harvey.
—Field Level Media