WASHINGTON -- The Washington Nationals used their speed and power to build a big lead against the Atlanta Braves on Saturday night.

Then they used their arms to preserve it.

Daniel Murphy smacked a two-run homer and drove in four runs, rookie Reynaldo Lopez pitched seven innings for his first win and the Nationals held on to defeat the Atlanta Braves 7-6.

Atlanta rallied from a 7-2 deficit in the ninth inning and Erick Aybar's two-run double off closer Mark Melancon made it 7-6, but Aybar was out trying to stretch it to a triple, as center fielder Ben Revere hit cutoff man Danny Espinosa, whose throw just beat Aybar.

"The game-saver was a relay that you work on all the time from Ben to Danny," Nationals manager Dusty Baker said. "He showed why he probably has the best arm in the league at shortstop. If he had a lesser arm, it would have been a runner on third (with Freddie Freeman up)."

Melancon then retired Freeman, who homered in the first inning, on a deep fly to right and Matt Kemp on a grounder to end it, picking up his 33rd save of the season.

"I knew I didn't get all of it," Freeman said. "Just a cutter in. I was looking in. I just didn't get to it in time. It's going to be hard for me to sleep on that one because it's a pitch I should hit."

Trea Turner homered and finished a double short of the cycle for Washington and Ben Revere had two triples.

"I think the reason why you get three hits is that you have three good at-bats. I was just trying to tell myself to do that," Turner said when asked if he was thinking about the cycle. "Obviously, I was just hoping to hit something somewhere where I could run to second."

Lopez (1-1), who won a matchup of 22-year-old rookie starters, blanked the Braves after Freeman's first-inning homer. Called up from Triple-A Syracuse for his third start, he allowed five hits, walked two and struck out two.

"I focused on working on my location, keeping the ball down," Lopez said through a translator. "That's what was working today."

To make room for Lopez, Washington (68-47) released former closer Jonathan Papelbon, who struggled in July and had made only two appearances since the team acquired Melancon from Pittsburgh.

Freeman's homer was his 23rd of the season, matching his career high.

Atlanta (44-73) has lost three of four, but battled back from a 7-1 deficit.

"We're never out of the game," Braves manager Brian Snitker said. "It was a really good rally. A lot of really good at-bats. Guys battling to the very end as they always do."

Braves rookie Rob Whalen (1-1) was hit hard in his third start, allowing six runs and six hits -- including two homers -- in five innings.

Right-handed reliever Jason Hursh, the 31st overall pick by Atlanta in the 2013 draft, made his major league debut and allowed a run and three hits in one inning.

Washington's Jayson Werth singled, extending his on-base streak to 42 games.

Right fielder Bryce Harper missed his fifth straight game with neck stiffness but received some positive news when an MRI of his neck came up clean. He remains day to day.

Freeman's homer gave the Braves a 1-0 lead in the first.

Washington quickly countered as Turner tripled leading off the bottom of the first. Two batters later, Murphy hit his 22nd homer of the year, a blast into the second deck in right.

"I was trying to go up and in on him there," Whalen said, "but I didn't get it up enough and he's one of the best hitters in the game and he just turned on it."

Turner struck again in the third, leading off with his third homer of the season. Revere tripled and scored on Murphy's sacrifice fly to make it 4-1.

In the fifth, Turner added a single and Revere followed with his second triple of the night. Revere then scored on Murphy's groundout and the Nationals led 6-1.

NOTES: The Braves recalled RHP Ryan Weber from Triple-A Gwinnett and optioned RHP Akeel Morris to Double-A Mississippi. ... An MRI on Atlanta RHP Chris Withrow's right elbow showed no ligament damage and he'll begin throwing again Tuesday. ... Washington RHP Joe Ross (right shoulder inflammation) played long toss on Saturday. Ross has been on the DL since July 3. ... Atlanta RHP Tyrell Jenkins (2-2, 3.92 ERA) opposes RHP Tanner Roark (12-6, 2.88) in Sunday's series finale. ... After Sunday, the teams still have 10 meetings remaining.