Nene scores 12 points in 22 efficient minutes Wednesday in Boston as Washington finishes 44-38 — the franchises’s best record since winning 45 games in the 2004-05 season. (Elise Amendola/Associated Press)

When the Washington Wizards gathered for training camp in September, they weren’t concerned about seeding, creating the ideal matchups or dodging opponents in the first round. They only focused on getting to the postseason, ending five years of misery and making good on owner Ted Leonsis’s demands to extend the season beyond 82 games.

Taking advantage of a weaker-than-expected Eastern Conference and the Brooklyn Nets’ late-season slide, the Wizards finished with the fifth seed after they defeated the Boston Celtics, 118-102, on Wednesday. They will face the Chicago Bulls in the first round of the NBA playoffs, with Game 1 on Sunday night at United Center. It will be a rematch of the 2005 first-round series that Washington won after ending an eight-year playoff drought.

“To be able to continue to play and have more to play for and a chance to try to compete for a championship, that’s better than anything,” Bradley Beal said. “We’re happy that we accomplished one of our goals, but now it’s got to be a new set of goals.”

The Wizards (44-38) were in danger of sliding to the seventh seed with a loss and a Charlotte win, but the fear of a possible first-round matchup against the two-time defending champion Miami Heat was enough incentive to take out the Celtics.

The Nets all but conceded the fifth spot by resting all of their starters in a loss to Cleveland that dropped them to the sixth seed. Washington owned the tiebreaker against Brooklyn, which allowed it to move up. When the Wizards stepped onto the floor for the regular season finale against the Celtics, they didn’t care about the implications of winning and certainly weren’t thinking about resting players in advance of a long-delayed appointment with meaningful April basketball.

The Post Sports Live crew discusses which Wizards player is most vital to the team’s playoff chances. (Post Sports Live/The Washington Post)

Beal scored a game-high 27 points and Trevor Booker scored all 20 of his points in the first half, when the Wizards shot a staggering 61.7 percent from the field and went into the locker room leading 68-56. The rebuilding Celtics made a run in the third quarter to get within four before the Wizards thrashed Boston for the second time this month.

Six players scored in double figures, with John Wall finishing with 15 points and nine assists and center Marcin Gortat recording a double-double with 15 points and 10 rebounds. Gortat joined the Wizards in October in a deal with Phoenix, and although the Suns won more games, they missed out on the playoffs in a more heavily stacked Western Conference.

“I didn’t expect the East was going to be so much weaker like it is right now,” Gortat said. “But end of the day, we still have a good team, we have a winning record and this organization hasn’t seen a winning record in a while, so I’m glad I’m a part of this team right now.”

With the win, the Wizards equaled the second-most wins for the franchise in the past 35 years. They also matched the Heat and Toronto Raptors with the most road wins in the East with 22 — an important number given the Wizards won’t have home-court advantage in the playoffs in any round unless there is a major upset.

Wall once scribbled “playoffs” on his sneakers, but he decided to write “we made it” for the rest of the ride to see where it takes them.

The Wizards went 2-1 against Chicago in the regular season, with their two wins coming with Nene in the lineup. The Brazilian missed the last meeting while recovering from a left knee injury.

“We didn’t say how many wins, but to be honest, we could’ve been a 50-win team if we didn’t let the beginning of the season hurt us and losing all those close games,” Wall said. “It’s amazing how our season has turned around and what we did as an organization.”

For a team that endured a 2-7 start that required a players-only meeting, couldn’t post a winning record until February and were without Nene for 29 games, the prize has been overcoming all of the hard times.

“That’s always satisfying when you go through an eight-month period of the grind and reach the last game and know that you have something to play for. It’s absolutely gratifying for those guys who have gone through some tough times in the past and reap the reward,” said Coach Randy Wittman, who will lead a team into the playoffs for the first time. “The resiliency of it — 82 games is a lot of ups and downs. Our lows we kept to a minimum, and that’s always a key in getting to the position we are today.”

Wizards President Ernie Grunfeld helped solidify the bench by acquiring veterans Andre Miller and Drew Gooden in late February, and 16-year veteran Al Harrington fought through ailments with his right knee to help the team complete its playoff push. The Wizards have been led by Wall and Beal, the back-court duo who have yet to make their playoff debut, but they are stocked with eight players with postseason experience, including Trevor Ariza (13 points), who won a championship ring as a member of the Los Angeles Lakers in 2009.

“Haters, where you are? Now you guys need to come here and congratulate us,” Nene said after scoring 12 points. “But it’s okay. If we didn’t have the haters, we couldn’t reach our goal, you know. I believe we can surprise if we play the right way. I believe in my teammates that we can do special things if we have each other and look to the same goal.”

For the first time in his career, Wall started all 82 games, completing another significant goal for a player who missed 33 games last season because of a left knee injury that derailed any hopes of the playoffs. Wall’s return last season revealed the potential of the team when fully healthy, and on Wednesday the Wizards delivered on that promise.

“I’m not planning no vacation nowhere, and that’s what I’m usually doing or going to see my family somewhere. Now they have a chance to come up and see me in a playoff series,” Wall said. “It’ll be my first time playing on [national] TV since my rookie year, so you don’t got to watch League Pass to watch us. But we’re here. We’re focused to try leave a statement and see where that takes us. We’re all focused and ready for the next part.”