BOSTON - The 76ers had a game plan.

But so had the Atlanta Hawks, New York Knicks and Chicago Bulls before them. So had each team during this record-setting win streak of the Boston Celtics'.

A "game plan" hadn't helped those teams much, and it didn't help the Sixers last night. The Celtics beat them, 110-91, for their 19th straight victory.

Boston improved to 27-2, the best mark ever for a two-loss NBA team. The previous record of 26-2 was shared by the 1969-70 New York Knicks and the 1966-67 Sixers.

The Celtics also broke the franchise record for consecutive wins, held by the 1981-82 team.

The Sixers knew beating the NBA champions at TD Banknorth Garden would be as difficult as buying a Yankees cap at Fenway Park.

Without leading scorer Elton Brand, who is recovering from a dislocated shoulder, and starting shooting guard Willie Green, who has a sore left ankle, the Sixers' game plan was to push the tempo and take care of the basketball.

They netted 20 points on the fastbreak, but had 22 turnovers - and the Celtics capitalized by scoring 29 points off them.

Even a well-executed game plan, which last night's wasn't, would only have challenged the Celtics' staunch defense, crisp ball movement, and energetic second unit.

"You basically have to play perfect basketball," said Sixers swingman Andre Iguodala, who finished with 14 points.

With 4 minutes, 53 seconds remaining in the second quarter, Iguodala dropped in one of his high-flying dunks to tie the game, 37-37.

Two turnovers, a foul, and four Boston baskets later, the Celtics led by nine points, and the Garden crowd seemed to recline in its seats, confident at last that this would end as most Celtics games do.

"The last three to four minutes of the first half, we let them get out in transition, we let them get layups, we let the game get away from us," Sixers coach Tony DiLeo said.

"When you're playing against a veteran team like that, when you get down like that, it's basically going to take the entire game to get back in it," said Sixers point guard Andre Miller, who finished with 14 points and eight assists.

Kevin Garnett and Rajon Rondo led Boston with 18 points each; Lou Williams and Marreese Speights came off the bench to score 16 each for the Sixers, who are 12-16.

The Sixers trailed by 14 at halftime and by 22 midway through the third period. Late in the fourth, with the lead at 17, the Celtics fans began chanting, "Beat L.A."

Even before this one had ended, attention had turned away from the Sixers and toward Boston's Christmas Day opponent.

While Boston looked ahead to a clash of NBA superpowers, DiLeo remained focused on the positives of his team's effort: 48 percent shooting, strong first quarter, solid bench contributions.

"There were some things we saw that we liked," he said. "I think this game will help us."

Contact staff writer Kate Fagan at 856-779-3844 or kfagan@phillynews.com.