WASHINGTON -- This past weekend in Pittsburgh, Braves manager Bobby Cox indicated that he could tell Kelly Johnson was tiring. Countless hours dedicated to honing his defensive skills at second base were taking their toll.

Cox wanted Johnson to cut back on the amount of early afternoon hours he was spending taking ground balls. But then, of course, the veteran manager also would have liked to have seen his first-year second baseman cleanly field the routine ground ball that changed the complexion of Wednesday night's decisive fifth inning at RFK Stadium.

Johnson's inability to secure Cristian Guzman's potential inning-ending double-play grounder allowed the Nationals to tally four unearned runs off Kyle Davies and claim a 6-4 win over a Braves team that simply saw its offense go to sleep over the course of the final five innings.

"Kelly has been brilliant," Cox said. "He's been the best second baseman in the league for me. You're allowed one once in a while."

Initially, Johnson's frustration caused him to leave the stadium without speaking to the media. But showing his class, the 25-year-old second baseman called two beat reporters to give his account of what led to just his third error of the season.

With Guzman facing a 3-1 count and the Braves leading by two runs with runners on first and second base, Johnson positioned himself a few steps back in expectation of a hard-hit grounder coming toward him. Unfortunately, he had to quickly react when the ball came off Guzman's bat softer than expected.

"It cost me the routine feel of turning a normal double play," said Johnson, who bobbled the ball twice before securing it. "I wanted to make sure we got at least one out and I ended up rushing myself."

Johnson's forgettable night ended with a game-ending strikeout against Jon Rauch, whose perfect ninth completed a stellar night for the Nationals' bullpen. After touching Levale Speigner, who was making his first start, for eight hits and four runs in the first four innings, the Braves managed just two singles against six different relievers over the course of the final five innings.

"I thought [the Nationals] pitched great," said Cox, whose own bullpen held Washington batters hitless and scoreless over the final 3 1/3 innings.

The most promising development of the night for the Braves was the scoreless eighth inning provided by closer Bob Wickman, who was making his first appearance since going on the disabled list on April 30 with tightness in his upper back.

For the most part, Davies deserved to be lauded for the effort he provided over the course of the first four innings. But the hanging curveball he served to Ryan Church ruined what had the makings of being a strong start. Church directed the hanger into right-center field for the decisive two-out, three-run double that capped the mistake-filled fifth inning.

"Kyle had Church [1-2] and if he bounces [the curveball], he probably gets a strikeout," Cox said. "He just hung it."

After Johnson misplayed Guzman's grounder, Ronnie Belliard followed with a grounder to short that was too soft to be turned into a double play, but effective enough to score a run. Davies then pitched around Ryan Zimmerman, who had a first-inning RBI double and fourth-inning solo homer.

When Davies threw two straight strikes to get the count to 1-2 against Church, it looked like he might escape the inning giving up just one run and holding on to a 4-3 lead. But because he hung the curveball, he was denied a second straight win and was forced to face the fact that he had to share the blame with Johnson.

"You don't want to blame anybody for a loss," said Davies, who allowed six runs -- two earned -- and five hits in 4 2/3 innings. "I could have got us out of the inning just as easily as that ground ball could have."

Davies, who felt he had the best changeup that he's had all year, was given an early lead courtesy of Andruw Jones' first-inning two-run single. Speigner, who had completed a season-high three innings on April 19, surrendered a Jeff Francoeur one-out double that led to two more runs for the Braves in the fourth inning.

But over the course of the next five innings, the Braves' only offense came via singles from Jones and Johnson, who is hitting just .209 since entering May with a .326 batting average. Still, he has now reached safely in 35 of his 37 starts and, for the most part, proven to be the capable leadoff hitter his team envisioned.

In addition, he has been a better second baseman than anybody could have predicted. But like anybody else who has ever played the position, he, too, is subjected to the potential of making that one costly error that can spoil what could have been a good night.

"There's nine guys on the field," Davies said. "[Johnson] is going to win a few games for us down the road. You can't sit there and point fingers."