John Lannan has cruised through seven innings, but a pair of singles to start the seventh proved too much for the Nationals left-hander to overcome. The Pirates scored a run on a double play, snapping a 2-2 tie.
Matt Diaz opened the seventh with a single to right and Neil Walker followed with a grounder between second and first. Second baseman Danny Espinosa dove to try to snag the bouncer, but it tipped off the webbing of his glove and skittered away into short right field, allowing Diaz to advance to third.
Lannan ended the inning by getting a pair of ground balls, but the first - to shortstop Ian Desmond - started a 6-4-3 double play that scored Diaz with the tiebreaking run. Eric Fryer then grounded out to short to end the frame.
In the bottom of the seventh, Lannan was pulled for pinch hitter Laynce Nix. The lefty allowed three runs on six hits, didn't issue a walk and struck out one. Sixteen of the 21 outs he recorded came on the ground.
The Nats mounted a two-out rally, with Roger Bernadina and Espinosa drawing walks. But Ryan ZImmerman took a called third strike from Daniel McCutchen to end the inning.