With the Braves trailing, 1-0, in the ninth, Jordan Parraz stroked a two-out RBI single to score David Rohm, who was inserted as a pinch-runner for Josh Wilson after Wilson drew a leadoff walk from Nationals pitcher Ryan Perry.
In the 10th, Jose Yepez and and Tyler Pastornicky hit back-to-back singles for the Braves off Perry before Jose Constanza was credited with an RBI on a grounder to Danny Espinosa, who committed a fielding error as the go-ahead run scored. Rohm then added a sacrifice fly.
Washington's Chad Tracy, who had two singles, added a sacrifice fly in the 10th for the final margin.
The game was scoreless until the bottom of the fourth inning. With Braves right-hander Tommy Hanson on the mound, Washington had runners on first and second with one out when Brian McCann was charged with a passed ball, advancing Ryan Zimmerman and Chad Tracy to third and second, respectively.
Jason Michaels came to the plate and grounded out to second baseman Dan Uggla, but Zimmerman scored on the play to give Washington a one-run lead.
Hanson pitched four solid innings and allowed the unearned run on one hit. Nationals left-hander John Lannan had his best outing of the spring, pitching four shutout innings, allowing three hits and striking out two.
Chad Durbin, Atahualpa Severino and Tyler Clippard followed Lannan and combined to pitch four shutout innings. For Atlanta, Adam Russell, Jairo Asencio, Anthony Varvaro and Yohan Flande (two innings) blanked the Nationals before Jose Lugo allowed a run in the 10th.
Up next for the Nationals: The Nationals travel to Jupiter Fla., to play the Cardinals on Thursday at 1:05 p.m. ET, live on MLB.TV. Left-hander Gio Gonzalez will make his fourth start of the spring. In three games, Gonzalez has allowed one run in 10 1/3 innings, with 10 strikeouts and four walks.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.