Danny Espinosa drove in three runs and Tyler Moore added a three-run blast as Washington downed Pittsburgh, 6-2, in the finale of a three-game set.
"He had great at-bats today. I was really pleased with his approach at the plate," said Nats manager Davey Johnson about Espinosa.
Wilson Ramos added three hits, while Roger Bernadina hit safely twice and Ryan Zimmerman scored two runs for the Nationals, who took two of three in the series.
Gio Gonzalez (3-2) worked six innings for the win, allowing five hits and a pair of runs, fanning five with two walks.
Starling Marte homered and Russell Martin posted an RBI double for the Pirates, but Wandy Rodriguez (2-2) gave up three runs on six hits despite seven strikeouts in defeat.
Bernadina's bunt single began the eighth, and he advanced on a Zimmerman groundout. After Adam LaRoche was given a free pass, Moore launched his homer to push the Nats' edge to 6-2.
"It fires you up. I would have done the same thing," Moore said of the intentional walk which preceded his homer.
Tyler Clippard followed with a perfect bottom of the eighth, and Rafael Soriano worked around a Brandon Inge double in a scoreless ninth.
The offensive fireworks kicked off when Marte began the home first with his fifth homer of the season, but not before an outburst by Nationals outfielder Bryce Harper -- who was ejected by third-base umpire and crew chief John Hirschbeck for arguing the third strike which ended the top of the inning.
Pittsburgh had the bases loaded later in the frame with one out and failed to generate any further offense.
"We had a chance to push him right out the door early, or at least create some separation," lamented Bucs manager Clint Hurdle.
Zimmerman walked to start the second, moved to third on a LaRoche double and scored on an Espinosa fly to center.
The Nats third baseman began the fourth with a single, moved up on a Rodriguez balk and later scored on Espinosa's two-run shot to left to put the visitors ahead 3-1.
Martin doubled home Gaby Sanchez for a 3-2 game in the bottom of the sixth.
Nationals center fielder Denard Span returned following a one-game absence with a bruised left foot, but Nats right fielder Jayson Werth sat out his third straight contest thanks to a strained right hamstring ... By allowing a Washington run in the second inning, Rodriguez ended his scoreless streak in PNC Park at 15 innings ... Entering play, Marte was hitting .407 (11- for-27) against left-handed pitchers this season ... Pittsburgh has lost four of six overall.