WASHINGTON — Brandon Beachy made one mistake in his matchup with Stephen Strasburg.

It was one too many.

Beachy allowed just three hits, one a home run to Jesus Flores, and the Atlanta Braves lost to the Washington Nationals 2-0 on Saturday.

Beachy, who has the National League's lowest ERA, kept the Nationals off the scoreboard through four innings. Three of his four walks came during that early stretch, but Washington's only hit was a single by Ian Desmond.

Then Nationals catcher Jesus Flores led off the fifth with a homer on a 1-2 count over the left-center field wall.

"Wasn't supposed to be elevated or over the plate," Beachy said. "That's what happens when you miss."

Strasburg pitched four-hit ball for seven sharp innings.

The Braves entered the series having won two straight, but have now lost 9 of 11. The series opener on Friday was rained out.

Beachy (5-4), who has lost three straight decisions, allowed a second run after a one-out walk in the seventh eventually came around to score against the Braves bullpen. Overall Beachy gave up three hits and struck out six over 6 1-3 innings.

"We couldn't have asked more out of Beachy," said Braves second baseman Dan Uggla. "He went out there and did his thing again."

So did Strasburg (6-1) — and then some. He completed seven shutout innings for the first time in his major league career. He opened the game with a flourish, striking out the first four batters.

Strasburg struck out nine, walked none and threw 90 pitches. Twice he gave up singles and then induced double-play grounders.

"That's the best I've seen him throw. He basically could do whatever he wanted today," Braves catcher Brian McCann said. "You throw that hard and you can command it like that, it makes it tough on the hitters."

Uggla struck out twice and grounded into a double play against Strasburg. In his previous at-bats against him, Uggla was 6 for 8 with two home runs and seven RBIs.

Playing defense in the seventh inning, McCann left the game after a pitch from Braves reliever Jonny Venters hit the catcher near his left knee. McCann sustained a bruise and is day to day.

Strasburg allowed multiple baserunners just once — in the third when Jose Constanza doubled and Michael Bourn singled with one out.

Sean Burnett gave up two singles in a scoreless eighth and Tyler Clippard pitched a perfect ninth for his fourth save in fifth chances.

Flores' drive into the left field bullpen was his second home run of the year.

In the seventh, Beachy was pulled with one out after Danny Espinosa walked. Espinosa stole second and Chad Durbin walked Flores.

Both runners moved up on the wild pitch from Venters. Espinosa scored on pinch-hitter Xavier Nady's double to right.

"Can't make mistakes in a game like that and I made far too many of them," said a frustrated Beachy, now with a 1.87 ERA. "I put people on and they're going to score."

NOTES: Atlanta SS Andrelton Simmons made his major league debut. He was 0 for 3. ... Washington RF Michael Morse made his season debut after missing nearly the first two months of the season with a strained back muscle. He grounded out to short in all four at-bats. ... Nationals manager Davey Johnson said that C Wilson Ramos would miss the rest of the season because doctors were unable to repair his torn anterior cruciate ligament and torn meniscus at the same time. When doctors repaired the meniscus, they thought the ligament needed time to heal and the ACL surgery will have to wait.