The Atlanta Braves' drive for the NL wild card spun its wheels again Sunday, with wild pitchers and missed opportunities at the plate contributing to a 4-2 loss to the last-place Washington Nationals.

Every Nationals player who scored got on base with a walk, the last two runs coming on Ian Desmond's tiebreaking single in the seventh that followed three straight free passes from the Braves bullpen.

The Nationals took two of three from the Braves, who began the day tied with San Francisco for the wild-card lead. The Giants beat Colorado 4-2 to move into a tie with San Diego for the NL West lead, pending the outcome of the Padres' game against Cincinnati later Sunday.

Atlanta has lost five of six. The Braves, who lost the season series 10-8 to the Nationals, now head home to finish up with a six-game stand against Florida and Philadelphia.

The Braves put two runners on base with fewer than two outs three times in the first six innings and failed to score each time. Rick Ankiel was the only Atlanta batter to produce runs, leading off the fifth with a home run and a doubling home Melky Cabrera with no out to make it 2-all in the seventh. Ankiel never budged from second after that hit, watching his teammates strike out twice and then ground out to end the inning.

Brandon Beachy, making his second career start, struck out nine over five innings to keep the Braves in the game. But the right-hander, who is playing a major role in a critical part of the season because Jair Jurrjens has a sore right knee, also walked three batters — and two of them turned out to be the only two runs he allowed.

Kyle Farnsworth (0-2) was even more off course, walking two of the four batters he faced. He entered in the seventh and got a pair of quick outs before walking Willie Harris and Danny Espinosa. Farnsworth was relieved by Jonny Venters, who promptly threw four straight balls to Nyjer Morgan to load the bases. Desmond then singled to center to put the Nationals ahead for good.

Sean Burnett (1-7) finally got a win this season for the Nationals by retiring six straight batters. He rescued starter Livan Hernandez from the seventh-inning jam and also worked the eighth before giving way to Drew Storen, who worked a 1-2-3 ninth for his fifth save. It was Burnett's first victory since Aug. 2 of last year.

The Nationals picked up single runs in the first and second innings on RBI singles by Michael Morse and Morgan. Washington's chance for a big inning in the second — they had the bases loaded with one out — came to end when Alberto Gonzalez tried to score out a fly ball to center and was thrown out by Ankiel for a double play.

The Braves had their chances against Hernandez. They had runners on first and third in the first when Brian McCann hit a hard liner right at first baseman Adam Dunn, who stepped on the bag for the double play. There were men on second and third in the fourth, but Alex Gonzalez popped up and Cabrera lined out to left. Gonzalez also hit into a double play to end the sixth, wiping out an inning in which the first two batters reached base.

Notes: Beachy got his first major league hit in the third inning, a ridiculous high bouncer that just cleared the pitcher's glove and went right between the charging second baseman and shortstop. ... The Nationals honored Atlanta manager Bobby Cox in a pregame ceremony, presenting him with a flag that flew over the U.S. Capitol. This was the last game in Washington for Cox, who is retiring at the end of the season. ... Hernandez made his 32nd regular season start against a Cox-managed team, tying him for first with Curt Schilling, Andy Benes and Steve Trachsel. Hernandez has started against a Cox team 34 times, including postseason, behind only Schilling's 35. ... Jim Riggleman won his 100th game since taking over as Nationals manager in the middle of the 2009 season. He's lost 131.