The Nationals pulled within 5 1-2 games of first-place New York in the NL East. The Mets dropped their second straight against the Boston Red Sox, 3-1. Washington gained ground on New York for the first time since Aug. 19.
Ryan Zimmerman also homered for the Nationals.
Zimmermann (11-8) won his third straight start. He gave up a run and seven hits, while striking out four and walking one. He allowed baserunners in six of seven innings.
Justin Bour ended Zimmermann's shutout bid with his 12th homer leading off the seventh.
Miami starter Tom Koehler (8-13) is still seeking his first win since July 23. He allowed five runs and nine hits over six innings in losing his seventh straight.