WASHINGTON - What chapped Terry Collins most about the festering Matt Harvey fiasco was how it overshadowed the bigger picture.

Lost in the hand-wringing about Harvey's innings limit, hidden in the vitriol directed at the designated diva, was the fact that the first-place Mets were still in a pennant race.

It is lost no more, not with the way Tuesday night played out, not with how Harvey failed in the most scrutinized start of his career, not with how the Mets rallied to beat the Nationals, 8-7.

They did it by doing on the field what they claim they have done in the clubhouse, by rendering Harvey and the drama that surrounds him a total non-factor. In the most scrutinized start of his career, Harvey tied a career worst by allowing seven runs in 51/3 innings. He was chased with his team behind 7-1.

But the Mets sent 12 men to the plate in the seventh, when they rallied to tie it against a command-starved bullpen that walked six batters in the inning.

Kirk Nieuwenhuis won it with his eighth-inning solo shot, the first pinch-hit homer of his career. It came against closer Jonathan Papelbon, deployed out of desperation, with the Nationals desperately needing a win after the Mets' stirring comeback on Labor Day.

That urgency failed to translate. Mets closer Jeurys Familia allowed the potential tying run to reach second base but slammed the door in the ninth, getting Yunel Escobar to tap into a game-ending 5-4-3 double play.

"We're playing like we don't have anything to lose, and that's what we need to do," Nieuwenhuis said. "I'm just going to enjoy the ride."

The Nationals, heavy preseason favorites to win the NL East, trail the Mets by six games. They must win Wednesday night just to avoid a sweep that could send them reeling from contention.

It was the Mets, of course, who began the series on shaky ground. Not only had they dropped two of three to the Marlins, but a dispute flared up over Harvey's innings limit.

Harvey and his agent, Scott Boras, insisted that doctors mandated a hard cap of 180 innings. The Mets contended no such number ever existed. The dispute remains, with both sides still working toward a compromise. The controversy turned Harvey into a villain, leaving vulnerable to fans who questioned his desire to pitch. His turbulent week unraveled further with one of the worst starts of his career.

The biggest blow came from Michael A. Taylor, who with an assist from centerfielder Yoenis Cespedes, chased Harvey with what amounted to an inside-the-park, grand slam single.

With the bases loaded, Taylor cracked a single to centerfield. But the ball bounced over Cespedes' glove and rolled all the way to the wall, clearing the bases and allowing Taylor to score on the three-base error.

Harvey, now up to 1712/3 innings, had stoked the rally by bobbling a bunt. The meltdown came after he had settled down after allowing three runs in the first two innings.

But the Mets mounted their furious two-out rally for six runs in the seventh, aided by Cespedes' bid for redemption and a Nationals bullpen that suddenly lost the ability to throw strikes. Their relievers' six walks included two with the bases loaded.

Former closer Drew Storen, brought in to restore order, allowed Cespedes' bases-loaded double and three consecutive walks. The nightmare ended only when Travis d'Arnaud -- the 12th Met to bat in the inning -- lined out to rightfield with the bases loaded.

By then, the damage had already been done, a 7-1 lead lost. It was the Mets' biggest comeback since 2011.