Nationals 6, Mets 2: Ross Detwiler pitched five shutout innings and Ian Desmond hit a leadoff home run as Washington dealt New York its first loss of the season.

The Mets, who entered the day as one of only four remaining unbeatens, were trying to start 5-0 for the first time since 1985. But they couldn’t generate any offense against Detwiler (1-0), who allowed two hits, walked one and struck out six.

The win was the Nationals’ fifth in the last six meetings against the Mets, who started the game with back-to-back hits but didn’t record another until the sixth.

Washington broke the game open with a three-run sixth. Ryan Zimmerman led off the inning with a double and scored on Jayson Werth’s RBI single to right. After Xavier Nady followed with a single, the Mets replaced starter Dillon Gee (0-1) with Bobby Parnell, who promptly gave up a pair of runs — one on a fielding error and another on Wilson Ramos’ RBI double.

Gee gave up four runs (three earned) on eight hits and struck out six in 5 ? innings.

Werth finished 4-for-5 with a pair of RBIs, including a run-scoring single in the seventh that stretched the Nationals lead to 5-0. Washington had 13 hits, compared to just seven for the Mets.

New York scored runs in the seventh and eighth on an RBI single by Justin Turner and a run-scoring double by Ronny Cedeno, who went 3-for-4 in his first start.

GAME NOTEBOOK: Ruben Tejada hit his NL-leading fourth double in the first inning … Mets third baseman David Wright was held out of the lineup with an injured right pinkie finger … Nationals closer Drew Storen (elbow) had a setback in his recovery and consulted Dr. James Andrews … Ike Davis struck out with two on in the seventh in a pinch-hitting situation, and is now 0-for-16 on the year with seven strikeouts.