Pittsburgh's three rookie regulars also made contributions as Pedro Alvarez hit a two-run double in the fifth, Jose Tabata had two hits and two RBIs and Neil Walker extended his hitting streak to 10 games. That helped the Pirates win for just the second time in seven games while handing Washington its third straight loss.
Zach Duke (7-12) pitched five innings for the win and left after failing to retire any of the four batters he faced in the sixth inning as Washington scored four runs to close to 8-5. He allowed four runs and five hits with three walks and five strikeouts.
Joel Hanrahan, the seventh Pirates pitcher, worked a scoreless ninth for his third save in six opportunities. He was twice removed as the Nationals' closer last season before being traded to Pittsburgh on June 30.
Livan Hernandez (9-10) was hit hard in his first start since signing a one-year contract extension with the Nationals last Sunday. He gave up eight hits and eight runs in 4 1-3 innings while walking two and striking out four.
Doumit had been hitting just .215 in 20 games being activated from the disabled list Aug. 7 after missing 15 games with a concussion. He got a rare start at catcher with most of his action in recent weeks coming in right field while Chris Snyder took over as the starter behind the plate. Doumit is hitting .281 when he is catching but .175 when he plays other positions.
Jones, mired in a 7-for-50 slump coming in and batting .144 in 31 games since July 28, doubled home two runs in a three-run third inning that put the Pirates ahead 3-1 and added an RBI double in a four-run fifth that pushed the lead to 8-1.
Washington center fielder Nyjer Morgan went 0 for 4 after learning he had been suspended for eight games by Major League Baseball for inciting a bench-clearing brawl on Wednesday night at Florida. Morgan appealed and is able to keep playing until his hearing on Sept. 10. He has also appealed a seven-game suspension from Aug. 25 for throwing a ball at a fan during a game at Philadelphia.
Espinosa opened the scoring with a drive into the right-field stands to lead off the top of the third.
The Pirates countered with three runs in the bottom half of the inning. Ronny Cedeno, who had two hits, led off with a double and scored on Andrew McCutchen's sacrifice fly. Jones then put Pittsburgh ahead with a two-run double to left field with two outs.
Doumit homered to center field, his 12th, to open the fourth, and the Pirates made it 8-1 with four runs in the fifth. Jones doubled in a run and Alvarez followed with a two-run double off the top of the center-field fence that chased Hernandez. Doumit greeted reliever Miguel Batista with an RBI single.
Bench coach John McLaren ran the Nationals as manager Jim Riggleman began serving a two-game suspension for his part in Wednesday's fight.
NOTES: RHP Stephen Strasburg, who struck out 92 batters in 68 innings and 14 starts in his rookie season, underwent reconstructive elbow surgery on Friday at Inglewood, Calif., and likely won't return to Washington's rotation until the start of the 2012 season. ... The Nationals activated RHP Garrett Mock from the 60-day disabled list and optioned him to Class AAA Syracuse. LF Josh Willingham was transferred from the 15- to the 60-day DL. Mock made one start on April 10 before undergoing surgery to repair a ruptured cervical disc in his neck. ... Pittsburgh 1B Jeff Clement, suffered a strained oblique muscle during his rehabilitation assignment with Class AAA Indianapolis and could miss the rest of the season. He is on the DL with left knee irritation.