Instead, they settled back into third.
"It feels pretty bad," said outfielder Scott Hairston, who gave the Mets their final lead with a solo homer in the 12th. "It was one of those games where it was going back and forth and we had a couple of unfortunate situations out on the field where things didn't go our way. But it's over with, and I guess we're just going to have to learn from it."
Though the Nationals stormed back to tie the game three times, it was not until the 12th that Harper pushed across the winning run against Elvin Ramirez. Mike Morse and Ian Desmond led off the inning with back-to-back doubles to tie things, with Desmond moving to third on Ramirez's wild pitch. Ramirez then loaded the bases with two walks before serving up Harper's opposite-field, line-drive single.
"I just lost my control a little bit," said Ramirez, who threw 47 pitches. "I wasn't tired."
Hairston gave the Mets their third lead in the top of the inning, homering off Ross Detwiler. He also singled, stole second and scored on Henry Rodriguez's wild pitch in the 10th. But the Nationals tied the game when Valdespin committed two errors at shortstop and Ike Davis misplayed a potential double-play ball at first base.
Andres Torres took Young off the hook two innings earlier with his two-run double against Craig Stammen, giving the Mets their first lead in the eighth. But proceeding with a shorthanded bullpen in the wake of Jon Rauch's elbow injury, Mets manager Terry Collins turned to Frank Francisco for a five-out save. The closer could not convert, allowing an inherited runner to score on Desmond's two-out single in the eighth.
That shorthanded bullpen proved to be a problem all night, with Collins hesitant to call upon Wednesday's starting pitcher, Jeremy Hefner, the last man standing in his 'pen. As a result, Ramirez stayed in the game despite his obvious struggles, and Harper did his damage.
"I don't think of him as a 19-year-old, but that's exactly what he is," Desmond said of Harper. "It's pretty cool to see the beginning of it."
But it was not all disappointment for the Mets. Making his first start since undergoing surgery to repair an anterior capsule in his right shoulder last May, Young allowed two earned runs (and one unearned) in five innings, giving up six hits and a walk. The Nationals scored once off him on Harper's RBI single in the third inning, then again on Ryan Zimmerman's run-scoring hit in the fifth.
The Mets supported Young on solo home runs by Valdespin and David Wright, enough to prevent their starter from taking the loss. And they were all encouraged by how he pitched.
"I feel like he's the same guy," catcher Josh Thole said, referring to Young's 1.88 ERA in four starts last season. "He could throw four pitches pretty much at will when he wanted to."
"I was just hoping that I wouldn't get overly excited to where I throw the ball all over the place," Young said. "I wanted to stay calm and hit my spots and work ahead in the count, and for the most part, I did that."
The Mets also have a blueprint for how to proceed with Young thanks to Johan Santana, who underwent a nearly identical procedure in September 2010. Last month, a few weeks before throwing the first no-hitter in Mets history, Santana chatted with Young and relayed some of the feelings and struggles he experienced during his own recovery.
"We've been through the same thing, and I'm very happy to see him back and helping us out," Santana said before Tuesday's game. "We'll see how everything goes. The recovery time is the key for everything, but he has done everything well to be here. ... Everybody's different. The way you heal, everything is different."
Like Santana, Young had garnered acclaim prior to his surgery as a tireless worker, leading Collins to lobby general manager Sandy Alderson to re-sign him this winter. When the Mets did ink Young to a Minor League deal during Spring Training, it seemed unlikely he would pitch in the big leagues this season, considering his prior injury history and Santana's own lengthy rehab blueprint.
But in taking the mound Tuesday, Young cracked that mold.
"I'm glad he's back," Collins said. "I'm really glad Sandy signed him. He's a first-class guy and I wanted to get him back."