But the season is far from over with the NLDS the next step.
Here is a look back 10 reasons the Nationals are going to postseason.
After signing with Nationals following the 2010 season, outfielder Jayson Werth felt the team was "a mess, upside down" before Davey Johnson became manager. To Werth, it felt like the team would never get to the postseason. But Johnson changed things after replacing Jim Riggleman in June of that year.
Johnson instilled confidence in his players, and it affects their attitude. Ian Desmond, for example, is having the best year of his career. It was Johnson who put in a new hitting philosophy: stop going to right field all the time and hit the ball where it is pitched.
General manager Mike Rizzo traded four Minor Leaguers to the Athletics for left-hander Gio Gonzalez, who has a chance to win the National League Cy Young Award. Gonzalez is one win away from becoming the second pitcher in franchise history to win 20 games in a season.
Last offseason, it looked like the Nationals would trade Adam LaRoche. They were trying to sign then-free agent Prince Fielder. The Nats didn't offer him a big enough contract, but they still had LaRoche, who carried the team the first month-and-a-half of this season. It didn't stop there. He leads Washington in almost every offensive category and is one of the best defensive first basemen in baseball.
Who needs a center fielder?
Michael Bourn and B.J. Upton were rumored as center fielders who could help the Nationals, but it appears they have one -- Bryce Harper -- for years to come. Harper was drafted as a catcher, but the Nats believed he could get to the big leagues quicker by putting him in the outfield. It turned out, Harper has great range and a great arm in the outfield. It also helps that Harper, 19, has been productive at the plate during his rookie year. He already holds the team record in triples, and he leads the team in runs scored with 87.
The pitching staff
The staff is first in the Majors in ERA. Yes, the Nationals have Stephen Strasburg, but the rest of their starting staff is not bad either. Gonzalez is an NL Cy Young Award candidate, and their two other starters -- Jordan Zimmermann and Ross Detwiler -- already have at least 10 wins.
The bullpen is just as good. Although Drew Storen missed the first half of the season, Washington didn't skip a beat with Tyler Clippard as the closer. Storen, Craig Stammen, Sean Burnett, Michael Gonzalez, Tom Gorzelanny and Christian Garcia are also productive for the Nats out of the bullpen.
Rizzo is a scout at heart, and nobody is complaining about the players he selected in the First-Year player and signed outside of the United States. Entering Friday's action, the Nationals have nine players on the Major League roster who were drafted by Rizzo and his staff since 2007. Overall, the team has 14 players who came from the farm system.
The Lannan game
On July 20, the Nats blew the largest lead in franchise history. They led 9-0 over the Braves but lost the game, 11-10, in extra innings. Johnson was clearly upset, and called it the worst game he had ever managed. Washington would go on to lose the first game of a doubleheader the next day against Atlanta.
Was this the sign of a major collapse? The answer was no.
Left-hander John Lannan was recalled from Triple-A Syracuse for the second game and pitched a solid seven innings, allowing just two runs on five hits to break a three-game losing streak. It was Lannan's first win since Sept. 21, 2011. Lannan would go back to Syracuse after the game. Lannan spent most of the season in the Minor Leagues because Detwiler beat him out for the final spot in the rotation.
No midseason trades
Johnson is proud of the fact that the Nationals didn't make any trades before non-waiver Trade deadline. If they needed a player, they could always go to the farm system. There was talk about acquiring a starting pitcher since Strasburg's season would come to an early end, but Washington was not willing to give up a lot of players to get that pitcher.
The health is back
During the first half of the season, the Nats were without Michael Morse and Ryan Zimmerman because of injuries. Once they came back, the offense went on a tear and the team ended up with one of the best records in baseball.
Who needs a leadoff hitter?
It was Johnson who stopped the talk of the Nationals needing a leadoff hitter -- at least for this year. Johnson inserted Werth at the top of lineup after the outfielder was activated from the disabled list. The move has worked out fine for the team. Entering Friday's action, Werth is 32-for-102 (.314) with 20 runs scored in 25 games.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.