No Washington baseball team has clinched a postseason berth in 79 years, and so one more day, or even few more days, makes for a short wait. But the Washington Nationals did not have to make it so painful on themselves on Wednesday night. They did not have to beat the grimmest of odds only to find the most wrenching way to lose. A blown call did not have to turn from a footnote to a turning point.

The Nationals nearly pulled off their latest, most incredible miracle before they lost, 7-6 in the nightcap of a doubleheader against the Los Angeles Dodgers. The Nationals, playing with half their regulars on the bench, rallied for six runs in the eighth inning to tie the score, only to watch Matt Kemp slam a game-winning home run off Tyler Clippard to lead off the ninth inning.

“That hurt,” Clippard said. “It hurt tonight, big time. That was a huge momentum shift, there in the bottom of the eighth for us. I think everybody in the ballpark, including myself, felt like we were going to win this game tonight.”

Behind Jordan Zimmermann’s one run allowed over six innings, Bryce Harper’s lightning bolt of a triple and exquisite infield defense, the Nationals won the day’s first game, 3-1. In the afternoon, sunbeams cascaded over the Capitol dome in the distance. In the evening, as Clippard closed the win and many thousand joined the few thousand who played hooky, the cool air made October baseball feel vividly near.

A second victory Wednesday night would have guaranteed the Nationals at least a wild-card spot and the city’s first postseason game since 1933. But the Nationals, with their magic number to clinch the National League East down to nine, gave it little thought.

“No clue,” Michael Morse told a group of reporters. “I learn stuff from you guys every day. Just keep the blinders on. Just keep pushing and pushing.”

After the opener, they never could have known what to expect. John Lannan unraveled over 32 / 3 innings as he made his second start since replacing Stephen Strasburg in the Nationals’ rotation. Dodgers right-hander Josh Beckett shut out the Nationals for seven innings, after which they trailed 6-0. Manager Davey Johnson had pulled veterans to keep them fresh, and Ryan Zimmerman, Adam LaRoche and Jayson Werth all watched from the bench.

Morse led off the eighth with a solo homer, saving the ignominy of a shutout. Ian Desmond followed with a single. Steve Lombardozzi, who had started for Danny Espinosa, turned on a fastball and roped the third homer of his career over the right field fence. Suddenly, the Nationals trailed, 6-3, and the park came alive.

“When Lombo hit the home run, that really sparked it,” Espinosa said. “At that point, I felt we had a good shot.”

With the score tightened, some Nationals could not help but think back to the fourth inning. The Dodgers had men on second and third with two outs, leading 5-0. Chien-Ming Wang was on the mound, making his first appearance since June 30.

Hanley Ramirez grounded to third, and Zimmerman knocked the ball down. He scrambled to retrieve the ball and tagged out Adrian Gonzalez. Replays showed the tag occurred before Kemp crossed home plate, before he had even reached the batter’s box chalk. After a confab, the umpires awarded the Dodgers their sixth run.

“At the time I guess you don’t think that’s a big play, but you can’t just give away runs in the big leagues,” Zimmerman said. “It was 5-0, and they just made it 6-0.”

Catcher Jesus Flores gave a damning report. He said he could hear one umpire tell the other umpires he thought the bases were loaded and did not have to make a call about the run. Crew chief Mike Winters declined to comment.

“Terrible call,” Flores said. “He thought it was the bases loaded, so he kind of didn’t pay attention. That’s why I guess he went to the other umpires and talk about it.”

Said Morse: “Calls like that, you never know when they’re going to come back and kick you in the butt.”

In the eighth, the Nationals trailed by three runs instead of two. They kept mauling Beckett. With one out, Corey Brown, in for Werth, reached second base on an error at first by Gonzalez. Mark DeRosa, a seldom-used veteran, roped a pinch-hit single to move Brown to third.

Here came Harper, the tying run, to hit off left-handed specialist Randy Choate. He squibbed a ball to third and beat it out, allowing the Nationals’ fourth run to score. In the bullpen, the phone rang for Clippard to start getting loose.

If not for the substitutions, Zimmerman would have batted next. Instead, Espinosa ripped a pinch-hit single to load the bases.

With two outs, Morse chopped a two-run single through the right side. The Nationals had come all the way back, a 6-0 blowout having morphed into a 6-6 tie.

“It was an awesome inning to be a part of,” Morse said. “You think, ‘What if some of the other guys were still in the game during that inning?’ That was one of the coolest innings I’ve been a part of on this team.”

The Nationals handed the ball to Clippard. He went ahead of Kemp with two strikes and then tried to strike him out with a high fastball. He threw it where he wanted, right below the letters. Kemp unloaded and sent the 93-mph heater into the red seats in center field.

“That’s a pitch for me that I’ve relied on a lot throughout my career, the elevated fastball,” Clippard said. “I don’t know if he was looking up there, guessed right, it didn’t have the life on it that it normally [does]. It’s even tougher to swallow knowing that I made the pitch I wanted to make and got hurt on it.”

Even with the messy nightcap, the Nationals ensured a rare feat. They became the first team to improve by at least 10 victories in three consecutive seasons since divisional play began in 1969. In 2009, the Nationals won 59 games and finished with the worst record in baseball. They won 69 games in 2010, then 80 in 2011. They have 90 wins and the best record in baseball, a half-game clear of the Cincinnati Reds.

“It’s been a rewarding experience, the whole season,” General Manager Mike Rizzo said. “I’m not here to talk playoffs or clinching or anything like that until it happens, or if it happens. But I think it’ll make a great statement in the city.”

The Nationals planned to acknowledge the wild-card berth, not to celebrate it. They would hold the champagne. They would choose discretion. They will party when, and if, they clinch the division.

“The only thing that’s going to mean anything to me is when we clinch the pennant,” Johnson said. “That’s the only number I’m concerned with.”