BOSTON - In 1966-67, when the 76ers started 26-2, the NBA was composed of 10 teams.

If every team carried a maximum of 12 players, which not every team did, that meant a total of 120 NBA players.

It was a far different era, light-years from the current league of 30 teams, with up to 450 players. It was the legendary era of Wilt Chamberlain and Bill Russell.

It was a time that melded into the end of the decade, when the '69-70 New York Knicks also opened the season 26-2.

No team had ever done better. Until last night. Until the Boston Celtics set a franchise record with their 19th straight victory. Until the Celtics turned back the Sixers, 110-91, in TD Banknorth Garden, led by 18 points each from Kevin Garnett and Rajon Rondo.

Some things - players, number of teams, rules - change. But some things stay the same.

Focus. Concentration. Effort. Defense.

Billy Cunningham has not only seen all of this before, he lived it. Cunningham was the star sixth man of the '66-67 Sixers, who were led by Chamberlain and included Hal Greer, Luke Jackson, Chet Walker and Wally (now Wali) Jones. Cunningham also coached the '82-83 champion Sixers of Julius Erving, Moses Malone, Maurice Cheeks, Andrew Toney and Bobby Jones.

"They've come back as hungry as they were last season," Cunningham said of the defending champions. "You see it in their effort, in the defense they're playing, in the growth of [Rondo and Kendrick Perkins]. It will be interesting to see what happens long term. Will they miss Posey [forward James Posey, who established himself as a force off the bench, then left in free agency]?

"They're enjoyable to watch. They play for one purpose, and that's to win. It's Garnett one night, it's [Ray] Allen one night, it's [Paul] Pierce one night. They understand why they're out there. I've watched parts of games, and I love the effort they give. And you have to like the [personnel] decisions Danny Ainge has made, bringing in Garnett and Allen. That can be risky business. They all make a lot of money, but they're not resting on their laurels. The game is still fun for them. It's still important to them."

The degree of difficulty in coaching a team of this caliber - from Alex Hannum in '66-67 to Cunningham in '82-83 to Doc Rivers now - is in maintaining focus.

"Doc's done a great job," Cunningham said. "That's the beauty of this team. The difficulty is in not getting ahead of yourselves, not thinking that the playoffs are the only thing that matters, taking care of business in the regular season first, keeping that drive, keeping that edge. They've been doing that marvelously."

The Celtics, like the two previous 26-2 teams, and like the '82-83 Sixers, play with a missionary zeal. When they defeated the Knicks, 124-105, Sunday, they had put together back-to-back games of at least 50 field goals for the first time since 1991. At the same time, they had scored more than 120 points in back-to-back games for the first time since 1994.After's Sunday's win, Pierce told Boston reporters they "haven't even talked about the streak, not once."

That's a consistent trait of great teams. Some things change. Some things never do.

Six shots

The Sixers were without

Willie Green

(sore left ankle) and

Theo Ratliff

(flu).

Kareem Rush

opened at shooting guard. *