It was like a Broadway production: The story line was predictable, but still it was fun to watch.

The Boston Celtics celebrated their first game as the NBA's defending champions tonight by showing just how much better they are than the downtrodden Washington Bullets, breezing to a 124-100 victory as most in the crowd of 15,320 roared their approval.

"The Celtics are a tremendous team and the newness of our team, well, it didn't make for a very close game," said Bullet Coach Gene Shue. "They start a very good team, then when they come in with their subs, it becomes very difficult to match up with them."

It was Celtic reserves Kevin McHale, Rick Robey and Gerald Henderson who led an 18-2 spree midway through the second quarter that turned Boston's 33-31 lead into a 51-33 cushion.

McHale blocked four shots and made seven of 11 shots in his 25 minutes.

"The difference was our bench," said Coach Bill Fitch. "The Bullets' bench hasn't played together as substitutes before. Heck, our subs have played together for three years. When they go in, I feel that's our biggest advantage over most teams."

The Celtics' regulars performed in their usual fine fashion, particularly Robert Parish. He led his team with 22 points and 12 rebounds despite playing only 26 minutes.

"We wanted to show everybody that we're the same club, that nobody had gotten a big head," the 7-footer said. "This was an important game for us, with all the ceremonies and everything."

The evening began with the presentation of championship rings by Commissioner Larry O'Brien, who said, "The Celtics proved themselves to be the greatest of the great."

Larry Bird, everybody's favorite, was selected to be the team's spokesman and during a surprisingly long streak of thank-you remarks, when speaking of team owner Harry Mangurian, the all-star forward said, "He made a smart move when he signed me."

Finally, admist a standing ovation, the players and Fitch hoisted the Celtics' 14th championship banner to the rafters.

"I got pretty emotional," Bird said after his 20-point performance. "When that flag was going up, that's when I felt like a champion. I thought back to all the work I've put into this game, and it all seemed worth it. It brought back a lot of memories.

"I tried not to get too emotional because we had a game to play and the Bullets are the kind of team that can sneak in here a steal a game from you."

The only sneaking the Bullets did was getting out of the arena following the one-sided affair that Boston led, 100-83, with 9:44 to play.

Greg Ballard, Washington's top scorer in the exhibition season, returned to his familiar small forward spot and led the Bullets' sputtering offense with 21 points. Center Ricky Mahorn, plagued by fouls, still managed 15 points and 12 rebounds.

"I thought Rick played very, very well until he made some careless fouls," Shue said. "When he went out with his third foul (with 10:14 left in the first half) it really hurt us."

When Mahorn departed, the Bullets were trailing, 31-27. Seven minutes later they were out of contention, 51-33, as McHale and Robey took charge of the reboundings and got the Celtics' running game going.

"That one bad spell killed us," said Shue. "Up until then, we had pretty good tempo, but we lost control. We became careless with the ball and they took advantage of it."

Although John Lucas played well in his debut, with 13 points and nine assists, the Bullets didn't have much opportunity to run because neither Jim Chones nor Spencer Haywood did much rebounding.

Haywood, signed as a free agent only seven days ago, committed five turnovers and appeared awkward at times. Chones was a last-minute starter, but made just two of six shots and had only two rebounds.

The Bullets are idle until Tuesday, when they play their home opener against Philadelphia.