ATLANTA -- Washington manager Davey Johnson opted to use left-hander Ian Krol in the 10th inning because three of Atlanta's first four hitters were left-handed. The strategy was foiled by the one right-hander batter in the order.
Justin Upton hit a solo homer off Krol (1-1) with one out to give the Braves a 3-2 win, their 19th final at-bat victory of the year. It was Upton's 23rd homer and second walkoff homer of the season.
"He made a bad pitch," Johnson said. "He left it up and he crushed it. Bad pitch. Bad location."
Upton continued his resurgence. He went 2-for-4 to increase his average to .273 and extend his hitting streak to four games. Upton now has 62 RBIs.
"He's sandwiched between those two left-handed hitters," Braves manager Fredi Gonzalez said. "You bring in a left-hander and they've got to come through him."
Krol retired Jason Heyward to open the inning. Upton worked the count to 2-2 and turned on a curveball for the third walkoff of his career.
"It's a great feeling when you go out and win the game for your team," Upton said. "There's nothing better than that."
The winning pitcher was Scott Downs (2-0), who worked a scoreless 10th inning.
The victory was the 18th in 20 games for the Braves, who have beaten the Nationals in 11 of 14 meetings this season and now lead them by 15 1/2 games in the National League East. The Braves are 10-4 in extra innings games.
The game featured a strong effort by promising rookie pitchers from each team, neither of them involved in the decision.
Atlanta's Alex Wood allowed one run and five hits and struck out nine in 6 1/3 innings. Washington's Taylor Jordan gave up two unearned runs, seven hits and three walks with three strikeouts in six innings.
"(Wood) has been terrific," Gonzalez said. "If you didn't know he was attending class a year ago, you'd think he's been around two or three years."
The Braves scored an unearned run in the first inning.
Jason Heyward led off with a single, extending his hitting streak to five games. He advanced to third base when Upton walked, but catcher Wilson Ramos threw to second to make a play on Heyward, who was running on a full count. Wilson's throw bounced into center field and allowed Heyward to reach third. He scored when Freddie Freeman grounded into a double play.
The Braves made it 2-0 with another unearned run in the third. Paul Janish singled and went to second with one out on Heyward's single, which just got over the glove of shortstop Ian Desmond. Upton hit a potential inning-ending double play ball, but second baseman Anthony Rendon took the relay and threw wildly to first, allowing Janish to score on the error.
The Nationals got a run in the fourth. Harper was hit by a pitch, went to third on Werth's single and scored when Desmond grounded into a double play.
Washington tied the score in the eighth against the Atlanta bullpen.
Ryan Zimmerman doubled with two outs and Bryce Harper was hit by a pitch from Luis Avilan. Jayson Werth greeted reliever Luis Ayala with an RBI single that found a hole on the right side of the infield. The run was charged to Avilan and ended a streak of 35 consecutive appearances without allowing an earned run.
Harper has now been hit by a pitch four times this year, three of those against the Braves. Although Harper was obviously upset about being plunked twice in the game, both sides agreed that neither was intentional. Wood hit Harper with a slow curveball and Avilan hit him with a fastball to put the go-ahead runner on base.
"I hope it wasn't (intentional) because it's ridiculous. It would be a ridiculous thing to be doing," Johnson said.
Gonzalez said, "To be intentional wasn't even close."
Washington has their opportunities. The Nationals had nine hits but could not deliver the clutch hit. A key moment was in the ninth when Denard Span grounded out to end the inning with runners on the corners.
"We couldn't get the hit," Johnson said. "We had the right guys up. We just couldn't get it done."
NOTES: Braves INF Tyler Pastornicky will have season-ending knee surgery to repair a torn ACL in his left knee. Pastornicky was injured in a collision with Heyward on Wednesday night. Atlanta recalled INF Phil Gosselin from Triple-A Gwinnett. To make room on the 40-man roster, the Braves placed RHP Cristhian Martinez (shoulder surgery) on the 60-day disabled list. ... The Nationals were facing a rookie pitcher on Friday for the 13th time this season.