Fresh from a three-game sweep in Philadelphia that dropped them six games behind the NL East leaders, the Braves entered Friday one-half game ahead of San Diego in the wild card race. They started Hudson, who had a 10-1 record and 1.55 ERA against the last-place Nationals.
Washington responded by battering its nemesis.
By the time Hudson left, Adam Dunn had hit two home runs, and the Nationals were on their way to an 8-3 win.
Hudson (16-9) saw his ERA rise to 1.91 against the Washington franchise, and the Braves were getting nervous.
"Every loss from here on out is tough. We've got to win ballgames... Tonight we just didn't do enough," Hudson said.
"I didn't do my job, I didn't make pitches when I needed to. Dunn really hurt us. Those two home runs got us behind the 8-ball."
Hudson allowed six runs and seven hits in 5 2/3 innings, equaling his career high with six walks.
Washington, which won its fourth straight -- its longest winning streak of the season -- denied retiring manager Bobby Cox his 2,500th win in his 4,500th game as a major league manager.
A quiet Cox spoke softly in his office, watching the Colorado-San Francisco game on television.
"We didn't pitch Dunn too good tonight," Cox said. "We just didn't hit. We've got to get some back-to-back hits here pretty quick. We didn't swing the bats real good tonight -- we can swing them a lot better than we did, that's for darn sure."
Dunn hit a solo home run in the second and a two-run shot off Hudson in the third, and a two-run single in the sixth. He's also an impending free agent and heard the crowd urge the team to re-sign him.
"It's really good to feel wanted. Who doesn't want that feeling?" Dunn said.
The Nationals were long ago eliminated from postseason consideration, but say it's fun to play against contenders.
"You've got to treat it like its our playoffs," Dunn said.
Harris, who played for the Braves in 2007, has his own incentive. The native Georgian had his mother and grandmother watching at home, rooting for him -- but still pulling for their home team.
"It's good to beat them, but you want to see Bobby Cox make it to the playoffs in his final year, but we also have a job to do here on our side," Harris said.
Harris hit a 3-2 pitch from Kyle Farnsworth off the wall in center field. The ball bounced hard off the wall and far from center fielder Nate McLouth, and the speedy Harris raced around the bases for the second inside-the-park home run in Nationals history and his 10th homer of the season.
It wasn't easy -- especially when he saw third base coach Pat Listach waving him around third.
"I was just tired, man," Harris said. "I thought I had a chance, but I wasn't sure I wanted to go."
Zimmermann (1-2), who missed most of this season after Tommy John surgery last July, won his first game since June 25, 2009. He threw five innings and allowed his only run on Omar Infante's eighth home run with two outs in the fifth. Zimmermann gave up three hits, struck out five, walked one and hit a batter.
A day after Stan Kasten announced he is resigning as president of the Nationals at the end of the season, Cox was asked whether Kasten -- his former boss in Atlanta -- would make a good baseball commissioner. "I think he would, yeah," Cox said. "He's smart. He knows the game. He's a lawyer. He loves baseball more than anything. He knows the inner workings of it. He'd be a solid choice, in my opinion." ... Nationals 3B Ryan Zimmerman was out of the starting lineup for a second consecutive game with a rib injury. Manager Jim Riggleman said, "The injury's in an area that we're going to be conservative with." ... Riggleman said he expects to have CF Nyjer Morgan back in the starting lineup Saturday. Morgan's eight-game suspension ended Friday. ... Cox said that RHP Jair Jurrjens, who is nursing a sore knee, won't pitch on Sunday. RHP Brandon Beachy will start instead. ... Heyward's streak of reaching base in 27 straight games ended. ... Wagner struck out the side in the eighth inning. He has 1,185 strikeouts -- fourth most for relievers -- two ahead of Rollie Fingers.