Ryan Zimmerman retreated to the video room late Friday night and replayed the central piece of the Washington Nationals’ unraveling. He saw himself throw what could have been the game-ending out into right field. Zimmerman watched Drew Storen stare into the outfield and chew on his mouth guard. He saw Davey Johnson gaze blankly from the dugout. It was all there — a defensive error, another stunned reliever and a manager trying to figure out how to halt the transformation of two of the Nationals’ presumed strengths into outright weaknesses.

In a 6-4, 10-inning loss at Nationals Park, the Nationals’ bullpen crumbled and their defense let them down. Tyler Clippard and Storen could not hold the three-run lead starter Ross Detwiler handed them after seven innings. The game-tying runs dashed home after Zimmerman fielded a chopper with the bases loaded and rifled the ball past Danny Espinosa at second base.

The disastrous ninth inning led to the ruinous 10th, when Ramiro Pena crushed a two-run home run over the home bullpen off Craig Stammen. As Stammen walked off the mound and fans fled for the exits, the collective ERA of Washington’s relievers stood at 6.34, second-highest in the major leagues.

“We need to do better,” Clippard said. “Ross pitched a hell of a game. It hurts. It hurts, obviously, for the club to get the loss. But it hurts for him. A bullpen, collectively, to have your starter do what he did and not get the win for him is very, very disappointing for us as a group and I know for me, too.”

The Nationals expected a tense confrontation in their first of 19 meetings with the Braves, who have lost only once this season, and their improved lineup. The divisional test, for one night, exposed a defense Johnson called “sloppy” even before the game and a bullpen trying to re-establish itself.

Fair or not, the Nationals’ collapse in Game 5 of the National League Division Series last year will hover in the late innings all season. Friday night, Storen had his first chance to close since October, and the game slipped through the Nationals’ fingers.

“I don’t think panic is the right word,” Zimmerman said. “We definitely need to learn from our mistakes. It’s the same thing that kind of got us last year, and why we didn’t maybe move on, because we couldn’t close games out both pitching and defense-wise. We need to get better at that and learn from our mistakes.

“But this bullpen is really good, and they’ve been good for a long time. Just like as hitters, the league adjusts to pitchers. They’re going to have to look, just like we do, go back and see what the hitters are doing to them now. And now it’s their turn to adjust, just like we have to do.”

Johnson wondered about his own effect on the bullpen. Nationals relievers have thrown 32 2 / 3 innings, tied for sixth-most in the majors, despite a starting rotation with an ERA a hair over 3.00. Friday night, he rested closer Rafael Soriano because he had closed the previous three nights.

“We’re just not locating the ball. We’re all over the place,” Johnson said. “I’ve got to take responsibility. Probably overusing them or something. . . . Det’s pitched two great ballgames and come out with nothing. I feel real bad about that.”