Larry Bird stole Philadelphia's last chance as the Boston Celtics defeated the 76ers, 102-100, tonight to win the Eastern Conference final, four games to one, and advance to the NBA championship series against the Los Angeles Lakers, who eliminated Denver, 153-109, to advance.

There, the Celtics will try to complete the league's first successful title defense since Boston did it by repeating over Los Angeles in seven games in 1969 after beating the Lakers in six in 1968.

Tonight's tense game was not decided until the final five seconds, when Bird stole the basketball from Andrew Toney, taking with it the 76ers' hopes of a game-tying shot.

The play came moments after Bird missed a driving layup. The long rebound was gathered in by Julius Erving, who collided with teammate Toney at midcourt. Erving recovered the ball and passed to Toney. But before the guard could make his move, Bird flicked the basketball away and dribbled out the game's final seconds.

The high scorer was Philadelphia's Maurice Cheeks with 26 points. Boston was led by Dennis Johnson's 23.

However, points scored were perhaps the least effective method of assessing contributions in this splendidly played game. Philadelphia rookie Charles Barkley had just 13 but nine came on three three-point field goals, each at a vital moment. The Celtics' Robert Parish had 20, but his 11 rebounds and almost majestic presence were more important.

Philadelphia blocked nine shots, Boston six. And the Celtics had 13 steals, the most important of which was Bird's. According to Toney, the play came just before he could signal for a timeout.

"I had the ball near our bench and I knew that there were just a few seconds left, so I started to go into a one-on-one move," he said. "Then, I heard someone hollering to take a timeout. I paused to hold up the ball and signal. That's when he rushed me."

The play, coming on a defensive switch, was the sort Boston made throughout the series. Many times the team's defensive front was so strong that it made the 76ers look disorganized on offense.

"Robert (Parish) can't guard Moses (Malone) alone, the same thing with D.J. (Johnson) on Toney," said Boston Coach K.C. Jones. "We had to get team help. Barkley was never able to do his moves and dunks and Toney was never able to really get loose, either."

Despite their troubles, the 76ers gave the defending champions all they could handle. They came back from a nine-point deficit, 73-64, in the third quarter, eventually going ahead, 81-77, with 12 minutes to play.

Most of that time, it seemed the visitors were just one step short of packing for their summer vacation. In fact, at one point -- 1:41 remaining in the game -- the sellout crowd of 14,890 at the Garden began the chant, "Beat L.A., Beat L.A.," anticipating the Lakers would be the championship opponent for the second consecutive season.

The chant appeared to be on the money when Johnson hit two free throws, making the score 100-95. However, eight seconds later, Barkley made the last of his three-point shots. Twenty-two seconds after that, Johnson hit a jumper to make the score 102-98. Erving, who shot six of 12 from the field after a five-for-31 slump over Games 3 and 4, scored on a drive and made it a two-point game with 56 seconds to play.

Boston ran down the shot clock before Bird missed a long jumper, but the Celtics maintained possession when guard Danny Ainge knocked the ball off center Malone's leg. Boston's second chance ended with the miss by Bird that introduced the hectic final seconds.

Not long after time had finally run out on the 76ers, a dejected Barkley only could speak of what might have been.

"We didn't take advantage of what was in front of us. We had our chances and blew them," he said. "We just blew the series. If we won last Saturday (Game 3), we win the whole thing.

"There were two great teams getting together. Unfortunately, they got the better of the situation, but we'll be back."

Bird's play in the final seconds was eerily reminiscent of one made by the Celtics' John Havlicek against the 76ers' Hal Greer in the final moments of the seventh game of the 1965 Eastern Conference finals, just one of many similar plays in the teams' storied rivalry.

This time, however, K.C. Jones -- a player on those '60s Celtics -- could take a deep breath in the locker room and say, "Free at last, free at last from their torment, at least for now. This was the toughest win of the series. We were struggling like hell and things were looking dim, especially those visions I had of having to go back to Philly."

That trip was avoided because of Bird, who emerged as a force despite a poorer-than-average series shooting from the field. Tonight, the nonpareil forward scored 17 points, but shot six of 18.

"I haven't played that well this round but the guys carried me," Bird said. "Hopefully, L.A. can be my series and I can carry them a little."