Just when the Mets thought they had something good going on, they went and got shut out by the Washington Nationals.

One night after earning a 6-2 win over the league's worst team — and despite out-hitting the Nationals 7-4 on Tuesday — New York suffered a 4-0 defeat, falling 10 games out of first place in the NL East.

John Lannan helped the Nats end a six-game losing streak, throwing a complete-game seven-hitter to improve his record to an even 7-7. The 24-year-old lowered his ERA to 3.38, throwing 106 pitches, striking out one batter, walking zero and earning 17 groundball outs. He only allowed one batter to reach second base.

New York's Oliver Perez (2-3, 7.68 ERA) threw a respectable six innings, allowing four runs on four hits with four strikeouts and six walks. Relievers Brian Stokes and Bobby Parnell combined for two perfect innings to finish the game, but the damage was already done.

Washington got on the board in the bottom of the fourth, when Alberto Gonzalez's fielder's choice scored Ryan Zimmerman and moved Adam Dunn over to third. Dunn scored on a single by Wil Nieves.

The Nats got two more runs in the next frame, courtesy of Dunn's RBI single and Josh Willingham's sacrifice fly.

Zimmerman finished the night 1-for-2 with two walks and two runs scored.

Jeff Francoeur, the only member of the Mets to finish with more than one hit, went 2-for-4, but that provides little comfort for his reeling squad. Since Carlos Beltran went on the disabled list on June 22, the Mets have suffered seven shutouts, five of which have come in their last 13 games.