
It was the second straight 1-0 Washington win in the series, which the Nationals took with three wins in the four games.
Pitching was the key to the series win, with the Mets scoring just six runs in the four games.
Fister (2-1) was solid on Sunday, giving up five runs in six and a third innings, striking out three and walking none.
Drew Storen picked up his seventh save with a 1-2-3 ninth.
Mets starter Dillon Gee took the loss, giving up a run on six hits in five innings, striking out five and walking five.
The series win pulls Washington (12-14) to four games behind of the first-place Mets (16-10) in the NL East.