Werth led off the fourth inning with a solo shot against Mets starter Jon Niese, one of two runs the left-hander allowed in six innings. Three days earlier, Werth had tagged Mets prospect Matt Harvey for a booming homer at Space Coast Stadium, estimated just shy of 500 feet.
The offense was plenty for Zimmermann, who limited the Mets to two hits and no runs in six innings. Zimmermann has not allowed a run three times in five starts this spring.
Niese fared nearly as well on Wednesday, striking out six batters over six innings of two-run ball, with five hits and a walk. But the Mets could not support him enough in the loss.
Both Zimmerman and Niese have enjoyed strong springs, lowering their ERAs to 3.32 and 3.98, respectively, in Wednesday's game.
In his Grapefruit League debut, Scott Hairston played six innings in center field for the Mets, finishing 0-for-3 at the plate. Hairston had been sidelined since early in camp with a strained left oblique muscle.
Lucas Duda's RBI triple with two outs in the seventh provided the Mets' first run of the afternoon, and Daniel Murphy capped the scoring with an RBI single in the eighth.
Up next for the Nationals: The Nationals play a split-squad games on Thursday. They play the Braves at 1:05 p.m. ET, with Edwin Jackson getting the start. That game can be heard on Gameday Audio. In his last outing, Jackson allowed 10 runs -- seven earned -- in a 12-3 loss to the Orioles. In the nightcap at 6:05, Minor Leaguer Mitch Atkins will throw for the Nationals against the Tigers in Lakeland. That game can be seen on MLB.TV.