Jon Niese worked in and out of trouble all but one time Saturday night, but that barely was enough for him to lose a battle of NL East lefties with Washington's Gio Gonzalez.
Niese gave up just one run despite scattering nine hits over seven innings, but Gonzalez blanked the Mets over that same span to send them to their fourth loss in five games, 1-0, to the Nationals before 39,730 at Citi Field.
The first-place Mets (16-9) managed only six hits against Gonzalez and three relievers for their first scoreless output of the year.