An eighth-inning Martin Prado RBI single broke a 2-2 tie, and Miami held on to beat Washington, 3-2, on Friday night, sending the Nats to their third straight loss.
Tanner Roark (1-1) took the loss in relief of starter Jordan Zimmerman, who gave up two runs on six hits in six innings, striking out four and walking none.
Miami reliever Bryan Morris (2-0) vultured the win with an inning of scoreless relief.
Steve Cishek earned his first save of 2015 with a 1-2-3 ninth.