NEW YORK (AP) — Wilmer Flores and the New York Mets seemed to be off to such a perfect start Thursday night.

Then the shaky shortstop made yet another error, fumbling away a routine double-play grounder, and things quickly unraveled.

Jacob deGrom struggled again and the Washington Nationals became the first visiting team to win at Citi Field this season, beating the Mets 8-2.

The Mets had opened 10-0 at home for a team record-tying 12-game streak over two seasons. Instead, they lost their third straight overall as part of a 2-5 rut.

"We got off to such a good start, certainly the last seven games have been disappointing," manager Terry Collins said. "Obviously we have to go back to doing what we did when we were playing well.

"One of them is not walking guys and the other is catching the ball. Hopefully, we'll start that again tomorrow and get some big hits when we need to," he said.

DeGrom (2-3) was perfect through three innings and, helped by Flores' double, held a 2-0 lead over Stephen Strasburg. The reigning NL Rookie of the Year issued a leadoff walk in the fourth and Yunel Escobar followed with a grounder that Flores bobbled for his sixth error this year.

"That's what your pitcher is looking for. You don't execute and you get frustrated," Flores said.

Jayson Werth's single, Ryan Zimmerman's sacrifice fly and Ramos' RBI grounder put Washington ahead to stay.

"When he makes the throwing errors, I think he rushes some of those. But today, he just missed it. He just dropped it," Collins said. "He was in the right spot, hands were in a good spot, he just dropped it.

"Certainly it changed the tide," he said.

Flores was chosen in spring training to start over Ruben Tejada, who had held the spot for the past two years.

"When we decided he was going to be the shortstop, you realize there might be a couple of rough spots," Collins said. "But we realize the minute we jerk him out of the lineup and throw him on the bench because he's not good enough to play shortstop, you might as well just put him someplace else because those days are over of playing shortstop.

"I think you have to be a little bit patient and continue to tell Wilmer, 'Listen, you've just got to slow down. Relax, and make the plays,'" he said.

Flores was booed by fans when he batted in the bottom of the fourth.

Bryce Harper hit two doubles, including a three-run drive in the ninth inning, as Washington won its third straight and matched its best streak of the season. The Nationals have won 15 of their last 16 vs. the Mets in New York.

Flores and Kevin Plawecki hit consecutive doubles and Curtis Granderson grounded an RBI single in the second off Strasburg (2-2).

DeGrom allowed five hits and three earned runs in 5 1-3 innings. In his last start, he was tagged for three homers and six earned runs in five innings at Yankee Stadium.

DeGrom had been 7-0 with a 0.95 ERA in his past eight starts at home.

"That was frustrating. I felt I had good stuff and there were a couple of times — the walks and stuff like that — and I got a little frustrated," he said.

TRAINER'S ROOM

Mets: 3B David Wright, out since April 15 with a strained right hamstring, is "making progress," Collins said. There's no timetable for him rejoining the team. ... RHP Rafael Montero will probably go on the DL because of stiffness behind his pitching shoulder, Collins said. Montero was brought up from Triple-A to start Tuesday and sent back to the minors after the game.

UP NEXT

An ace matchup Friday night when RHP Max Scherzer (1-2, 1.26 ERA) returns to the Washington rotation to face RHP Matt Harvey (4-0, 3.04). Scherzer missed his last scheduled start after jamming his right thumb while batting. "I hope that thumb bothers him a little bit," Collins kidded. Harvey shut down the Nationals earlier this season and "is back to full force," Williams said. Harper is 0 for 10 with five strikeouts lifetime vs. Harvey.

LAST ONE

The Mets became the last team to lose at home this season. They were trying to become the first club to start 11-0 at home since the 2009 Dodgers won their first 13.