WASHINGTON -- Sean Doolittle knows how important each game the Nationals have remaining against the Braves can be. It’s why he was so hard on himself after giving up a solo homer in the 10th inning to Braves third baseman Josh Donaldson, the difference in Washington's 5-4 loss at Nationals Park on Wednesday afternoon.

Doolittle did not throw a bad pitch, but his elevated fastball, his go-to weapon, drifted toward the outer half of the plate instead of up and in, where he has had success against Donaldson in the past. Donaldson deposited the ball 407 feet into center field, spoiling the Nationals two-run ninth-inning comeback and the Nats' attempt to gain ground in the National League East.

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The Nationals wasted a prime opportunity against the team directly in front of them, dropping two out of three games this week to the Braves, which pushed them to 6.5 games back in the NL East.

"When you're trying to track a team down, you can only hope to get so much help from the rest of the League when you're trying to move up the standings,” Doolittle said. “It's really important in those head-to-head matchups to take care of business. Today's game, it just kind of had that feeling that we were going to find a way to get it done as we have so much of these last couple months. But [we] just fell a little bit short."

The loss squandered the comeback effort by the Nationals, just shortly after general manager and president of baseball operations Mike Rizzo overhauled the team’s bullpen with three veterans arms just before the 4 p.m. Trade Deadline. The Nats trailed by three runs until Matt Adams’ pinch-hit two-run homer with two outs in the eighth inning. In the ninth, they plated a pair of runs against the Braves' relief combo of Luke Jackson and Sean Newcomb to push the game into extra innings.

But in the top of the 10th, Donaldson got a fastball up and on the outside corner from Doolittle and lifted it into center field, keeping Washington from inching closer in the division.

“I wanted to win this game,” manager Dave Martinez said. “But the boys left it all out there today. Fell short. We’ll come back. Plenty of baseball left. We play these guys a few more times. Let’s just keep playing good baseball.”

The two teams engaged in a different sort of arms race during the past two nights. At the end of Tuesday’s game, the Braves acquired reliever Chris Martin from the Rangers, who a source told MLB.com the Nats were also working to acquire. Then, near the end of Wednesday's game, Atlanta traded for Tigers closer Shane Greene, who had been connected to Washington for weeks.

The Nationals can still feel good about their day Wednesday, however, after adding right-hander Daniel Hudson from the Blue Jays, along with left-hander Roenis Elias and righty Hunter Strickland from the Mariners, to improve a bullpen that owns the highest ERA in the Majors.

“Even though we've had to cover I think the fewest innings as a group, as a bullpen, there's still some of us that could use some reinforcements,” Doolittle said. “[Wander] Suero comes to mind. He's done an outstanding job. I'm so proud of the way he's continued to battle all season long. ...I think every time I go into a game now, I'm setting a new high in games pitched, in innings pitched as a National. So, we're all feeling it a little bit, it's that time of the year. It will be good to have some new toys.”