Ian Desmond is tagged out by Atlanta Braves third baseman Martin Prado. (Scott Cunningham/GETTY IMAGES)

In one of their more peculiar games of the season — this less than 24 hours after a man in a wedding dress jumped onto Turner Field — the Washington Nationals were unable to overcome multiple lead changes, an early injury to their starter and spotty relief during a 9-8 loss to the Atlanta Braves on Sunday afternoon.

Blowing advantages in the fifth and eighth innings, the Nationals finally succumbed in the series rubber match when Freddie Freeman’s single off reliever Ryan Mattheus with two outs in the ninth scored Martin Prado to end it. Prado had reached on a fielder’s choice and stolen second, and by the time he touched home plate, most of the 30,314 in attendance had risen from their seats in celebration.

Washington, meantime, was left to piece together the aftermath of its second loss in three games, fifth in its last seven and fourth in a row by a single run. The Nationals (47-48) dipped below .500 for the third time in five games and fell nine games behind their NL East rival in the wild-card chase.

They had a chance to go back ahead in the ninth with runners on the corners and two outs, but Jayson Werth grounded to short. The $126 million free agent acquisition is 10 for 76 since June 24 and batting .213 for the season.

“It’s always frustrating. We were in a position to win the game,” Mattheus said. “When you walk away with a loss when you’re in a position to win the game, it’s tough to swallow.”

The Nationals had grabbed an 8-7 lead in the sixth courtesy of Danny Espinosa’s two-run homer, but all-star reliever Tyler Clippard was saddled with his fifth blown save, surrendering the equalizer two innings later on Nate McLouth’s blast over the right field wall. Espinosa’s homer, his team high 17th, followed a five-run fifth for the Braves (56-39) that included Brian McCann’s tying three-run blast and a go-ahead RBI from Alex Gonzalez for a 7-6 lead.

The combination of Henry Rodriguez and Sean Burnett yielded those runs in relief of Tom Gorzelanny, who departed after two innings with a right ankle strain from running into McCann on a play at home.

“It’s always disappointing when you can’t do your job, and you put pressure on the bullpen, make them throw the rest of the game,” Gorzelanny said. “It hurts them in the long run. It’s unfortunate, but there’s nothing you can do.”

Washington’s offseason addition to the rotation hardly could have had a more precarious beginning, first walking leadoff hitter Jordan Schafer. The center fielder soon stole second and advanced to third on Jesus Flores’s low throw that was ruled an error. Flores was starting at catcher in place of Wilson Ramos, who received the day off after playing in the first two games of the series.

Prado, batting second, fought off three foul balls before singling to center to drive in Schafer, then swiped second with one out and Freeman at the plate. The first baseman walked, and Dan Uggla did the same when facing a 3-1 count; Gorzelanny was charged with ball four when going to his mouth while on the mound. The left-hander clearly didn’t agree with the call and had an exchange with the umpiring crew that brought Manager Davey Johnson out of the dugout momentarily.

With the bases loaded and Alex Gonzalez up, Gorzelanny threw low and well to the left of Flores, who was unable to prevent the ball from rolling behind him. That wild pitch gave Prado plenty of room to score while the runners behind him each advanced one base.

Gonzalez flied out to right field, where Jayson Werth promptly threw back into the infield as Freeman feigned making a break for home. Gorzelanny escaped further damage by inducing McLouth’s grounder to first to end the inning.

Gorzelanny, however, found himself in harm’s way in the top of the third after reaching on a fielder’s choice bunt that Freeman scooped and threw to second to get lead runner Ian Desmond, who had walked to start the inning. Roger Bernadina tripled off starter Jair Jurrjens, and after Gorzelanny rounded third, he collided with McCann in front of the plate just as the throw from cutoff man Uggla reached the catcher.

The impact jarred the ball loose, allowing Gorzelanny and Bernadina to come home on what was scored a throwing error by Uggla. But Gorzelanny walked gingerly back to the dugout, favoring his right ankle, and although he came back to the mound to test it before the home half of the third, he wound up walking off with trainer Lee Kuntz.

Rodriguez replaced Gorzelanny and pitched a perfect third, and his teammates helped the cause in the fourth with a four-run barrage that included six hits, four for extra bases. Espinosa tripled in that sequence for a 5-2 lead, narrowly missing a home run when the ball hit the yellow stripe lining the top of the outfield wall, and came home on Ryan Zimmerman’s double.

Atlanta erased that lead soon enough by batting around in the fifth, with Rodriguez allowing Schafer’s single that scored Wilkin Ramirez to cut it to 6-3 and Burnett yielding the homer to McCann and RBI groundout to Gonzalez.

“Me blowing a three-run lead is a big blow to the team for sure,” said Burnett, who replaced Rodriguez after 21 / 3 innings. “It happens. They’re a great ballclub, and winning teams find ways to come back and at least tie it up and give themselves a chance. They did it off me, and they were fortunate to get a ball in the zone and did it off Clippard, too, so just one of those days you’ve got to regroup.”