The victory snapped a seven-game road losing streak for Colorado.
The game made it to extra innings after the Nationals scored in the ninth off Rockies closer Adam Ottavino, who had not allowed a run in a club-record 31 1/3 innings, spanning 37 games. Ben Revere drew a one-out walk, then stole second base. Trea Turner nearly drove him in, but he was robbed in center field by a sliding catch from Blackmon. But with two outs, Jayson Werth drove a single into left field to tie the game at 4.