The Bullets topped off a splendid season's work last night by wrapping up the NBA's best record with a performance worthy of a champion.

Playing against a disorganized, uninspired bunch of Boston Celtics, Washington scored its season high in a 145-119 romp before 10,193 at Capital Centre.

It was a $50,000 payday for the club, running its regular-season winnings to $100,000-and the playoffs haven't even started.

The Celtics were hardly a formidable opponent without a flu-ridden Bob McAdoo and injured player-Coach Dave Cowens, who stayed in Boston for ankle treatments. But the Bullets weren't about to back into the best record. They wanted to clinch the honor last night and they met their goal with a steamroller first-half effort.

The game wasn't 12 minutes old before it was all but over. The Bullets ran off an 18-2 spurt just before the end of the opening quarter to grab a 37-21 lead; they could spend the rest of the night counting their winnings.

Washington's domination was so great that Bob Dandridge, hardly a shot-blocker by choice, swatted away a career-high five attempts in the first 10 minutes of the contest. He finished with eight blocks, 27 points and seven assist in only 28 minutes.

And everyone on the team could join in the fun. Elvin Hayes, running the court like a rookie, chipped in 20 points. Mitch Kupchak registered 19 points and 16 rebounds. Four other players had at least 12 points apiece.

Washington shot 56 percent, mainly because Boston's defense missed the plane and was still in Beantown. And the Bullets posted a season-high 42 assists, Larry Wright contributing 11.

"It was fun to play out there," said Coach Dick Motta. "Our bodies were alive. We could have played with anybody. We've been playing all year for the best record and for the money and it was good to wrap it up.

"We won (the title) last year without the home-court advantage, so now we'll try it a new way. But you have to have the percentages in your favor, since home teams with 67 percent of the games in this league."

Hardly anyone figured Washington would wind up on top of the 1978-79 regular-season heap despite last June's championship. But the kind of team effort produced last night-complete with balanced scoring and bundles of points from the front line-belied all the predictions.

"Everyone thought Philly or San Atone would win the conference," said Hayes, who is ending the most impressive season of his 11-year career. "They felt the Bullets were a fluke. Now we've won the conference and the best record and we are the best in the league.

"I think we have shown we are a good, solid basketball team. We've overcome injuries and adversity and didn't cry about them. We have a veteran team and we are relaxed."

But even Hayes, the man with the seemingly bionic body, was glad to get the best-record race over with. Now, with three games left in the regular season, he wouldn't mind "cutting down on my minutes and maybe coming off the bench. Let the other guys start."

Motta, however, doesn't want the team to relax too much. "We have an obligation," he said, "to play hard against teams still trying to get play-off spots like Atlanta (Saturday) and Houston (Sunday). But I'll give people like Mitch and Kevin (Grevey) and Greg (Ballard) a lot of time."

The Bullets will get back guard Tom Henderson for the last games. He has been out with a sprained knee but said last night he will test out his recovery over the weekend. Wright, however, will miss the contests because of a death in the family.

In keeping with their image, the players didn't have any kind of after-game celebration honoring their achievement. Nor were the hometown fans particularly boisterous, although the crowd pushed attendance over the 500,000 mark for the first time in the team's history.

But the game didn't inspire emotion.

The Celtics, finishing off a horrible season, hardly put up a fight. It was so easy for Washington that Wes Unseld, returning after missing two games with bronchitis, stayed around for a half, scored six points and grabbed eight rebounds, then went home.

That 18-2 first-quarter run showed off the Bullets at their best.

Hayes put on a shooting display, making the first three baskets with long jumpers, all from different spots on the floor. Then Wright took over, dashing the court for a couple of his quick-as-light field goals, and Dandridge finished up with a driving layup and a pair of free throws.

"Bobby and Elvin were something in the first quarter," Motta said. "But, then, they've been something all year." CAPTION: Picture 1, Wes Unseld rebounds as Kevin Grevey breaks for basket.; Picture 2, Bullet Bob Dandridge goes over Cornbread Maxwell. Photos by Richard Darcey-The Washington Post