Miami's pitching staff limited Washington, playing with a split squad on Saturday, to just four hits, only one for extra bases.
The Marlins offense asserted itself early against Nationals starter Gio Gonzalez.
Marcell Ozuna collected three RBIs. He started the scoring in the first inning with a two-run double to center and added a run-scoring single in the third. Donovan Solano knocked in run later in the third inning with a single to right.
Gonzalez, making his second Grapefruit League start for the Nationals, allowed four runs on four hits, along with a pair of walks and strikeouts, over 2 2/3 innings.
Up next: Max Scherzer makes his third start of the spring when the Nationals travel to Kissimmee to face the Astros at 1:05 p.m. ET on Sunday, live on Gameday Audio. In two starts this spring, Scherzer has allowed two runs on eight hits and struck out five in five innings. Casey Janssen and Taylor Jordan are also scheduled to pitch.
Jamal Collier is a reporter for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.