Facing a six-run deficit with seven outs remaining, the New York Mets mounted an improbable rally and stunned the Washington Nationals 8-7 on Wednesday on the back of a pinch-hit, go-ahead homer from unlikely hero Kirk Nieuwenhuis.

Trailing 7-1 in the seventh, the comeback included eight straight Mets reaching base with two outs in the inning - including six walks - highlighted by a bases clearing 3-run double from Yoenis Cespedes. He would score the tying run after the Nationals bullpen walked the next three hitters in what has been a disasterous series from Washington.

The Nats built their lead by jumping on Matt Harvey for three runs in the first two innings, then seemed to break it open in the sixth when Michael Taylor singled to center with the bases loaded. The hit scored a runner, but an rare mis-play on the ball by Cespedes allowed three more runs to score (somehow Harvey was charged with seven earned runs, despite what seems to have been a 3-run error).

With momentum in hand for New York in the eighth, Nieuwenhuis - who was cut by the team earlier this year, then signed and cut by the Angels and resigned by the Mets - stepped up as a pinch-hitter batting .192 with three homers on the year - all three having come in one game. But it didn't matter, as he took former Phillies closer Jonathan Papelbon (3-2) deep to right-center and once again scattering Nationals fans from the park early.

After seeing their division lead fall to four games entering the series, the Mets extended their advantage to six, having snagged the first two of three. They'll send Jacob deGrom to hill looking for a sweep on Wednesday, facing Washington's Stephen Strasburg.