Is this game really necessary? Hasn't this scene been played before?

The Philadelphia 76ers have come here to play the Boston Celtics Sunday in the seventh and deciding game of the NBA Eastern Conference final (WDVM-TV-9, 3:30). They also have come here to escape the gloom of Philadelphia.

"It's good that we're playing the final game in Boston," Julius Erving said after the 76ers blew a 15-point lead and lost, 88-75, Friday night in the Spectrum. "We'd better get out of town before people run us out."

There already is talk of wholesale change for the 76ers, perhaps starting with Coach Billy Cunningham, if the team repeats its collapse in last year's conference final. Last year, the 76ers lost the last three games to the Celtics.

Once again this season, Philadelphia built a 3-1 advantage in the best-of-seven series. Then the 76ers were beaten, 114-85, here in Game 5 and scored only 11 points in the fourth quarter of Game 6.

The word choke is one of the most overused in sports, often employed simply to explain a golfer missing a short putt or a kicker a short field goal attempt.

However, when a team doesn't sink a jump shot in the second half, when it makes just seven of 34 shots (and two of those on goal-tending calls), when only one player, Julius Erving, scores in the final five minutes of the most important game of the season, the word seems appropriate.

Now, so soon after that humiliating experience, the 76ers must come out in public again. They must face a national television audience, plus one of sport's most boisterous crowds in steamy Boston Garden, where the Celtics have beaten them by 40 and 29 points in the past two weeks.

"You can't say a game is a foregone conclusion," Boston's Cedric Maxwell said when asked what he thought of the 76ers' mental state. "Confidence is a big factor in this game, though, and it just isn't there for them right now.

"I'm sure they're telling themselves it's not over, that there's one more game to play. But if they're going to look deep down, inside their hearts, they know they lost a golden opportunity."

Discussing the final 4 1/2 minutes Friday night, when Philadelphia was outscored, 14-2, Maxwell said the 76ers seemed to know they were going to lose.

"You could see the look in their faces," the four-year veteran forward said. "They looked almost shell-shocked. I don't think they wanted the ball. They weren't shooting well and they didn't want the ball."

All the talk of choking and jinxes tends to denegrate the magnificent defensive effort of the Celtics. Defense and rebounding has been the determining factor in the last two games and should be again Sunday. This is Boston's strength.

Only an extraordinary scoring performance, such as Caldwell Jones' 22 points in Game 2 or Andrew Toney's 39 points in Game 4 can offset the Celtics' huge advantage in these essential areas.

After the second game, Jones has settled back into his usual routine and scored 30 points in the last four games. A perceptive defensive adjustment by Boston Coach Bill Fitch has limited Toney. In the last two games, the 76ers' scoring leader has made only seven of 31 shots.

"I tore down (on film) every basket he made last Sunday," Fitch said. "He's a great shooter and we can't afford to let him go where he wants. You can't stop him one-on-one, so we made some adjustments."

Danny Ainge, embarrassed by Toney a week ago, has made a remarkable improvement. His defense earned 32 minutes of playing time Friday night because he made only two of 12 shots.

"The more film you watch, the more you learn about somebody," said Ainge, a rookie from Brigham Young, at today's workout in Boston Garden. "I hadn't really played against him much in the season. But it's a team defense. We're switching, doubling up and getting a lot of help from the big men."

Gerald Henderson has taken over as the floor leader in place of Nate Archibald, who suffered a dislocated shoulder. Henderson has helped Ainge as much as anyone by crowding Toney, forcing him to abandon his jumper and drive to the basket where shot-blockers Robert Parish and Kevin McHale are lurking.

"Not too many layups go down this time of year," Henderson said. "We're just trying to funnel Andrew into all those trees."

Henderson said it will be important for the Celtics to get off to a good start today because they don't want the 76ers to regain their confidence. He's also counting on Boston's 76th consecutive sellout crowd.

"Boy, is it going to be loud," he said, grinning widely. "As soon as we get on the court, they'll go crazy. Our crowd gets pumped up and that gets the players pumped up. That's what the home-court advantage is all about and we've got it back now. It feels good."