New York — New fan favorite Wilmer Flores hit a leadoff homer in the 12th inning to give the New York Mets a 2-1 victory over the Washington Nationals on Friday night in the opener of a pivotal series between the top teams in the NL East.

Two nights after endearing himself to Mets rooters when they saw him wiping tears away at shortstop after he thought he'd been traded, Flores received four standing ovations on an invigorating day for New York.

Just a few minutes before the 4 p.m. trade deadline, the Mets gave their meager offense a major boost by obtaining slugger Yoenis Cespedes from Detroit for two minor league pitchers.

Hours later, Flores drove in both Mets runs and made a spectacular defensive play at second base to back Matt Harvey.

The 23-year-old infielder drove a 1-1 pitch from Felipe Rivero (1-1) to left-center for his 11th home run and first in 147 at-bats since June 12 against Atlanta.

Fans jumped out of their seats and roared in a delighted frenzy as Flores pumped his arm in the air and circled the bases, pointing to the word "Mets" written across his chest when he came around third.

He tossed his helmet aside and was swarmed by teammates who rushed to home plate to celebrate. New York pulled within two games of first-place Washington and washed away the sour taste of Thursday, when the Mets squandered a six-run lead in a gut-wrenching loss to San Diego.

As fans filed out of Citi Field, they chanted "Wil-mer Flores! Wil-mer Flores!"

Carlos Torres (4-4) struck out the side in the top of the 12th.

Nationals slugger Bryce Harper was ejected in the 11th after taking a called third strike and screaming right in the face of plate umpire Jerry Meals.

Harper, now 0 for 17 against Harvey, had reached base safely in a career-best 26 consecutive games before going hitless in five at-bats. The fourth-year outfielder has been tossed six times in his career, three this season.

Flores put the Mets ahead in the fourth against Gio Gonzalez with a two-out RBI single off the glove of diving shortstop Ian Desmond.

Yunel Escobar tied it in the eighth with a two-out RBI single on Harvey's final pitch.

An energetic and vocal crowd of 36,164 turned out for the opener of a three-game set, the most significant series in years for the Mets.

"I think it's really important for us," manager Terry Collins acknowledged. "We've got to make up some ground here so we can stay in the hunt."

Harvey was up to the occasion. He retired his first 16 batters before Jose Lobaton singled in the sixth, prompting a collective groan and then a warm hand from fans who began chanting "Harvey! Harvey!" an inning earlier.

The right-hander, who entered with a 1.34 ERA in seven career starts against the Nationals, was backed by a string of exceptional defensive plays as the Mets carried a 1-0 lead into the eighth.

Flores stretched out for a diving stop in the first, earning his first standing ovation of the night.

Harvey got the first two outs in the eighth before pinch-hitter Clint Robinson was hit by a pitch on the foot. The call stood after a replay challenge by the Mets. Anthony Rendon reached on an infield single, and Escobar singled sharply up the middle on a 2-2 fastball that registered 97 mph.

Trainer's room

Nationals: RHP Stephen Strasburg (left oblique strain) is slated to throw 80-85 pitches Monday in his second rehab outing for Triple-A Syracuse.

Mets: C Travis d'Arnaud came off the disabled list and returned to the lineup. He had been out since June 21 and missed 33 games with a sprained left elbow. It was only the 20th start this season for d'Arnaud, sidelined from April 21 to June 10 with a broken right pinkie. For now, the team plans to give him a day off after each set of two and then perhaps three consecutive starts over the next week to 10 days. ... LF Michael Cuddyer (left knee inflammation) is expected to begin playing rehab games in the next few days. "He's feeling a lot better," Collins said. ... LHP Jerry Blevins (broken left forearm) was finally cleared Thursday to begin a throwing program. He was injured April 19. ... LHP Jack Leathersich, who was at Triple-A Las Vegas, had Tommy John surgery Thursday. Leathersich went 0-1 with a 2.31 ERA in 17 games for the Mets this season.

Up next

Nationals rookie right-hander Joe Ross (2-3, 3.03 ERA) starts the middle game of the series against All-Star RHP Jacob deGrom (10-6, 2.05). The last time they matched up on July 21 in Washington, deGrom and the Mets won 7-2. Over his last 12 starts, deGrom has a 1.37 ERA.