"Two of three? It's just not enough. We just can't afford to lose," Johnson said. "It's that simple. We just need to get back at it tomorrow."
The Nationals are now 5 1/2 games behind the Reds for the second and final National League Wild Card spot, with 10 games remaining.
Nationals right-hander Ross Ohlendorf was given a 2-0 lead in the fifth inning. With the bases loaded and one out, Jayson Werth drew a walk, allowing Anthony Rendon to score. Left-hander Alex Wood and Braves manager Fredi Gonzalez argued with home-plate umpire CB Bucknor about the call before Gonzalez was ejected. Bryce Harper followed with a sacrifice fly, scoring Denard Span.
But disaster struck in the top of sixth inning against Ohlendorf. Dan Uggla, a .183 hitter entering Wednesday's action, swung at the first pitch -- a fastball -- and homered over the left-field wall. It was his 22nd home run of the season.
Jordan Schafer was the next hitter, and he reached base on an infield single, but Ohlendorf threw the ball past first baseman Adam LaRoche for a two-base error.
"I didn't do a good job fielding it," Ohlendorf said. "I don't think my feet were tangled up necessarily."
It looked like Ohlendorf was going to get out of the inning when he struck out pinch-hitter Joey Terdoslavich and induced Elliot Johnson to pop up to third baseman Ryan Zimmerman. However, like Uggla, Justin Upton swung at the first pitch -- a slider -- and hit a two-run home run over the left-center-field wall to give Atlanta a one-run lead.
"I just made a couple of bad pitches in the sixth," Ohlendorf said. "I thought I pitched well after [Schafer] got on third. But I made a bad pitch to Upton. He did a good job hitting it. I felt strong the whole time. I felt it's probably as good as I've pitched. I'm just disappointed how it turned out."
Uggla hinted that the strike call by Bucknor and subsequent ejections of Gonzalez and then Wood may have sparked the Braves to victory.
"Things like that, sometimes they can start something," Uggla said. "Sometimes, the other pitcher is going to bear down and whatever. Then right after I hit that homer, Jordan did a great job of putting one down and putting the heat on them and got all the way to third. That was an awesome play."
Outside of the sixth inning, Ohlendorf was solid, allowing the three runs in six innings. He struck out six and walked none.
The Braves added an insurance run the following inning against right-hander Craig Stammen. Pinch-runner Andrelton Simmons scored all the way from first on a double by Brian McCann.
A bright spot for the Nationals was Span extending his hitting streak to 29 consecutive games, which is a game short of the team record set by Zimmerman. In the seventh inning, during his last at-bat of the game, Span singled to right field off reliever Luis Ayala. However, he was erased on a fielder's choice by Zimmerman.
"I was definitely pumped to extend it. The first three at-bats was against a tough pitcher -- Wood. He is tough to pick up from a lefty," Span said. "Once Ayala came in there, I was able to see the ball a little bit better. I just buckled down. I wanted to get it and I did."
But the Nationals need more than just keeping Span's hitting streak alive. They need to start another winning streak. The Nats now play a four-game series against the Marlins, who have the worst record in the NL. While the Nationals are known to take the one-game-at-a-time approach, they know a sweep of the Marlins is crucial.
"At this point, we know we can't lose, but we did. We definitely could have won today and should have won," Span said. "With 10 games left ... right now, it's a must-win every day. That's the way we have to approach each and every day from here on out."