John Havlicek had heard the speech many times before, but he sat there on the floor of the suburban Lexington Christian Academy gynmasium and listened intently as the dapper little than with the smoldering cigar talked to the Boston Celtics for 15 minuts this morning.

The man was Red Auerbach, the fiery Celtics president and general manager and former coach. He was making a rare appearance at a Celtic practice to deliver an emotional speech about playing with that old Celtic pride, intensity and enthusiasm.

Auerbach had not seen those traits in Wednesday night's humiliating 110-91 loss to the Philadelphia 76ers, a defeat that put the Celtics down in the series, 3-2. They face elimination from the playoffs when the teams meet again Friday night in Boston Garden.

At Inglewood, Calif., Friday night the Los Angeles Lakers and Golden State Warriors resume their series, tied 2-2.

Auerbach was infuriated by the Celtic's lackadaisical performance in Philadelphia. He was incensed when he learned Havlicek and guard Jo Jo White had criticized coach Tom Heinschn for what they believed to be ill-advised first-quarter substitutions.

"We went from a two-point game to a 21-point game," Havlicek said. "I thought we should have stayed with the people we had in the game . . ."

"I'm not saying you can't go to the bench," added White, "but I don't know if that was the right time."

Auerbach didn't want to hear any more of that talk, and he said so today. "If you're going to lose," he told his team, "then lose like champions."

Auerbach also spoke about forgetting the past and "putting everything you've got as professional basketball players" into Friday night's sixth game.

This was one message surely not directed toward Havlicek, a man who has given his body and his soul to this team for 15 brilliant years, eight of them on NBA championship teams.

And today, Havlicek could only smile when asked if he thought he had just participated in the final practice session of his career -- a distinct possibility if the 76ers wrap up the series.

"You know that was the furthest thing from my mind coming over here," he said. "But I guess it could be (his last practice) as much as it might not be. Who knows?"

No one can say for sure what Havlicek will do next season. Although he says, "I love playing basketball more than anything else I could possibly do," he also says he is still undecided about coming back in 1977.

He is 37 years old, playing with a bad knee on a team that has taken a roller-coaster ride through the 1976-77 NBA season, a regular soap opera in sneakers.

"It's been very frustrating," Havlicek admitted. "It is a high followed by a low almost every other night. We have no consistency. We're a pretty good rebounding team, but we're not as good defensively and our shooting is down from last year, too.

"We've had five changes on the roster from last year's team. I know everybody says we don't look like the Celtics they've seen in the past, and we're not. We haven't been together long enough to get to that point."

Havlicek still is functioning as a man Celtic assistant coach John Killilea describes as "the all-time all-around basketball player in the history of the game, and the most intelligent."

He is averaging 40 minutes, 20 points, seven assists and six rebounds in this series, all improvements on his regular-season averages. He is having difficulty handling Julius Erving on defense, but who doesn't?

"I'm the fist to realize I'm not the player I once was," Halvicek said. "I'm performing at a lower standard than what I'm accustomed to. But I still think I'm playing at a higher level than a lot of guys around the league.

"There's no question that the players now are faster, stronger, better shooters and jumpers than when I came into the league.

"But as far as knowing the fundamentals, how to box out, set a screen or take a charge, the players today shortcut those things because of their superior physical talents. Nobody thinks.

"That's what disturbs me the most. When I first came into the league, everybody on this team had a great understanding of the game. Look at all the guys I played with back in the '60s who are coaches now. How many guys in the era, say, after 1970, are going to be coaches? Not many."

Havlicek said he had no desire to coach the Celtics or any other team when he does retire. He also insists he will leave the game on his terms.

"I don't want to hang around as a token-type player, either, depriving some young kid of a job just so I can hang on a little longer. I want to play the game like I always played it and I still think I can."