Moses Malone scored a season-high 33 points and got 18 rebounds last night to lead the Philadelphia 76ers to a 122-105 victory over the Boston Celtics in the Spectrum and give Coach Billy Cunningham his 300th NBA triumph.

Maurice Cheeks scored 22, Julius Erving 19 and Clint Richardson 18 as the 76ers defeated their Atlantic Division arch rival for the second time in three games this season.

Richardson scored 11 points in the first quarter. He led a run of 13 consecutive points that enabled the 76ers to take control. Richardson sank two jumpers as the 76ers scored the final six points of the period for a 32-28 lead.

The Philadelphia margin grew to 79-62 on a Richardson dunk with 7:22 left in the third quarter. Larry Bird then led a 9-1 surge that helped the Celtics cut the lead to nine, but Cheeks sparked the 76ers the rest of the quarter and they took a 91-77 lead into the fourth period.

Cunningham reached the 300-victory mark faster than any other coach in NBA history. Last night's game was his 430th coaching.

"It just doesn't make that much difference," Cunningham said. "Now, if I can last long enough to achieve what someone like Bear Bryant has, maybe I can say that my record does make a difference."