Chris Carter's pinch-hit RBI double was the go-ahead run in a six-run eighth inning as the New York Mets rallied for an 8-6 win over the Washington Nationals Tuesday night at Citi Field.

Washington took a 3-0 lead on Adam Dunn's seventh homer, a three-run shot in the first off Jonathon Niese. The Nationals pushed the lead to 6-1 in the fifth on a two-run single by Ivan Rodriguez and an RBI single by Ian Desmond.

But Desmond's throwing error in the eighth helped open the door for New York's big inning against relievers Brian Bruney, Tyler Clippard and Miguel Batista.

Rod Barajas' two-run double, Angel Pagan's RBI single and Carter's RBI double came against Clippard (6-1) and Batista walked Jason Bay with the bases loaded to pad the lead.

The rally made a winner out of Raul Valdes (1-0), who worked around a hit and a walk to pitch a scoreless eighth.

Francisco Rodriguez retired the Nationals on six pitches in a perfect ninth for his fifth save in seven chances.

Bay and David Wright had three hits apiece for the Mets and Jeff Francoeur also drove in two runs.