Michael Morse wallops a three-run, upper-deck homer with two outs in the ninth inning to rally Washington to a 6-4 victory over the Marlins in Miami. It was Morse’s 30th home run of the season for the Nationals, who have won 13 of 16 games. (Lynne Sladky/Associated Press)

The Washington Nationals wish this season would not end, or at least that it would last a little longer. They are winning too much and having too much fun to want it to stop now.

Late Monday night, Michael Morse crushed a game-winning home run and thrust his right fist in the air before his left hand even let go of the bat. Watching the replay later, he could not believe he did that. He just got wrapped up in the moment, which doubled as a marker for his franchise.

For the first six seasons of their existence, Washington finished last five times and fourth once. The Nationals, then, can count the results from Monday night as progress. Morse’s game-winning, three-run homer in the ninth inning gave them a 6-4 victory over the Florida Marlins and solidified their first third-place finish in the National League East since baseball returned to Washington.

The Nationals remain 91 / 2 games behind the second-place Atlanta Braves. But they are a team that lost 298 games the previous three seasons. They are 13-3 in their last 16 games, and nine of those 13 wins have been started by a pitcher age 25 or younger. Third place will pass for disappointment next year. It stands as an accomplishment this season.

“A lot of these guys wish there was another month left,” Morse said afterward, clutching the ball that commemorated his 30th home run. “We’re showing teams we could turn this division around soon. We want to win a World Series. To win a World Series, you have to win a division.”

Even before Morse’s heroics, another result on the other end of the Eastern Seaboard ensured this year would be different, anyway. The New York Mets’ loss to the Cincinnati Reds would have clinched third place for the Nationals even if they lost.

Manager Davey Johnson noticed when the game went final on the Sun Life Stadium scoreboard. He entered the day knowing third place was at stake.

“I had my lineup out there, didn’t I?” Johnson said. “It wasn’t our goal to end up in third place. We have not accomplished anything. You only accomplish something if you’re fighting for a pennant. But we’ve made a lot of strides, and we’re going in that direction.”

The Nationals, at 79-80 with two games remaining against the Marlins, can also finish with a winning record for the first time. They have Morse’s milestone home run to thank. Morse won the game by becoming the fourth Nationals player to hit 30 homers. Few of them have been more meaningful than Monday’s upper-deck blast.

Against closer Edward Mujica, Laynce Nix scalded a leadoff, pinch-hit single. Ian Desmond followed with his second hit on the night, a line drive to left field. The rally appeared to fizzle when Rick Ankiel could not drop a sacrifice bunt and ultimately struck out. The runners both moved into scoring position when Ryan Zimmerman grounded out to shortstop.

Up came Morse, the Nationals’ cleanup hitter. The words surely look more dramatic than the action felt. Football yard markers crisscrossed the grass and the University of Miami’s ‘U’ logo was leftover from Saturday’s game in shallow center field. Mere dozens of fans quietly sat and watched. The Nationals, though, have played in September like every games means something — if not everything — to them.

Morse settled into the box most aware of Mujica’s lethal change-up. He planned to stay back and try to hit fastballs to the opposite field, and “that would keep me on the change,” Morse said.

Mujica threw Morse two fastballs, and then a 1-1, 89-mph change-up.It hung over the heart of the plate, and Morse destroyed the ball. He knew immediately. So did Mujica, who crouched on the mound and covered his head. The ball landed over the scoreboard and rattled around the seats.

“He was more concerned with hitting .300 than 30 home runs,” Johnson said. “He just accomplished both with one swing. And there was no doubt.”

Morse had seemingly reached the apex of his season Sunday afternoon, when he launched a homer in the Nationals Park finale and received the first curtain call of his life. Monday night, he added another memory to his breakout season, the first in which he spent no time in the minor leagues. He has 94 RBI and a .303 average to go with those homers.

“This whole year, being able to know I’m in the lineup was a big accomplishment for me, being able to bat in the middle of the order,” Morse said. “The little stuff means a lot to me this year.”

Said Desmond: “I played with Mike a little bit in 2009 in Triple A. He’s hungry. He’s out to prove to people he can play.”

In the bottom of the ninth, Johnson turned to Henry Rodriguez to close the game out. Drew Storen had pitched on consecutive days, and after Rodriguez’s unreal performance Sunday, “He deserves a right to have an opportunity to finish the game,” Johnson said. Rodriguez faced the minimum, ending the game with a 4-6-3 double play made possible by an earlier diving play from second baseman Danny Espinosa.

Afterward, shortly after Morse chuckled at a replay of his home run celebration, several Nationals veterans sat at a table, one of their last postgame dinners together. They ate, talked and listened to “Amber” by 311.

They don’t want their year to end, but Wednesday afternoon it will. In the manager’s office, Johnson thought about what he’ll say to his third-place team then.

“You had a great year,” Johnson said. “Congratulate yourself on that. But this isn’t what we’re after. We’ve got to take another step.”