If ever there was a rap against Julius Erving, it was that the Doctor doesn't play defense.

Larry Bird and the Boston Celtics found out to the contrary tonight.

Erving's defense on Bird keyed the 76ers to a 110-100 victory over the Celtics before a capacity crowd of 18,276 at the Spectrum, and gave them a 2-1 lead in the best-of-seven NBA Eastern Conference championship playoff series.

Erving guarded Bird for the first time in the series and overplayed him so much that the Celtics looked disoriented and never got ther offense clicking.

Bird, who had 33 and 34 points in the first two games of the series in Boston, had only 22 tonight, a total Erving matched.

"It's not every day that I get to talk about my defense," Erving said. "I find it a little difficult because usually it's getting criticized."

Not tonight.

"It's best not to let Bird get his hands on the ball at all because he can do so much with it," Erving said. "I was face-guarding him and I think it surprised him. He played basically a guard position the first two games and he was so effective because of his outside shot.

"Tonight I just tried to keep the ball away from him. They seemed content to try and run their regular offense and they didn't run anything special for Bird until the second quarter, and they were playing catch up by then."

They never made it.

The Celtics were down by 11 at the end of the first period. Bird had only three points.

Caldwell Jones had started on Bird the previous two games and because Bird was playing outside, it took Jones, the 76ers' best rebounder and shot-blocker, away from the basket. He had seven rebounds and no blocked shots the first game and five rebounds and one block in the second. But tonight, by playing inside the whole game, Jones had 14 rebounds and blocked five shots.

Darryl Dawkins got into early foul trouble and played only 22 minutes, so Jones played center half the time. He helped make it a miserable night for Boston's Robert Parish, who made only one of 14 shots from the floor.

Boston Coach Bill Fitch said the switch of Erving to Bird didn't surprise him.

"They did the same thing in the third game last year," he said. "Even with Erving doing a good job on Bird, Larry scored 22 points and played well enough for us to win. Too many others guys didn't.

Obviously, one of the "other guys" was the 7-foot Parish, who played only 22 minutes because of his ineffectiveness.

Fitch has been dissatisfied with Parish's play the entire series and has started going to rookie Kevin McHale and Rick Robey more often.

The 76ers moved ahead to stay midway through the first quarter. The score was tied, 10-10, when Erving led them on an 11-0 scoring binge from which the Celtics never recovered.

Erving started the rally with an 18-foot jump shot and then assisted Maurice Cheeks and Lionel Hollins on consecutive fast-break buckets. After a jumper by Hollins, Erving blocked Bird's shot and fed Bobby Jones for a three-point play. In a span of 90 seconds, the Sixers had built a 21-10 lead.

The lead grew to 18 points in the second quarter, as sensational rookie Andrew Toney came off the 76er bench to score eight points in the period. He finished with 19.

The Celtics made one strong charge in the final quarter. McHale, with 12 points in the period, started bringing them back when the 76ers hit a dry spell.

In one stretch, Philadelphia missed five straight shots, four of them medium-range jumpers by Erving.

"When you play defense the whole game, your offense suffers a little," Erving said. "My legs were tired and I was getting up on my jump shot."