Charles Barkley had 31 points and 20 rebounds and Maurice Cheeks had 27 points as the Philadelphia 76ers rallied from a 18-point deficit to beat the Bucks, 118-112, last night in Milwaukee in the opener of their Eastern Conference semifinal best-of-seven series.

The Bucks played without all-star guard Sidney Moncrief. The 76ers played without Moses Malone and Bob McAdoo. All are injured.

The 76ers took a 97-96 lead with nine minutes left when Barkley scored off a rebound. The Bucks rallied to lead at 101-97, but Philadelphia outscored Milwaukee by 16-7 for a 113-108 lead with 51 seconds left.

Alton Lister's layup with 19 seconds left cut the margin to 114-112. Barkley was intentionally fouled a second later and hit two free throws to make it 116-112, then Clemon Johnson made a pair with 13 seconds left to seal the victory.

Terry Cummings led the Bucks with 23 points. Paul Pressey had 20.

*Celtics 119, Hawks 108: Larry Bird scored 36 points, including eight in Boston's game-ending 10-0 run, as the defending league champions won at home for a 2-0 series lead. The best-of-seven series moves to Atlanta Friday night and Sunday.

Boston, which has won 35 straight home games, built an 87-69 lead in the third period. Atlanta started rallying when a basket by Dennis Johnson was nullified and Celtics guard Danny Ainge was ejected with 3:54 remaining in the quarter.

Ainge jostled with Atlanta's Scott Hastings while Johnson was going in for a layup.

The Hawks pulled to 109-108 with four minutes left. Here, Bird took charge.

Bird also had eight rebounds, seven assists and two steals. Atlanta's Kevin Willis had 23 points.

*Rockets 119, Nuggets 101: Lewis Lloyd scored 13 of his 23 points in the third quarter and Ralph Sampson scored 27 points as Houston, at home, took a 2-0 lead in its best-of-seven series against Denver. Denver has lost eight straight games at the Summit.

Games 3 and 4 of the Western Conference semifinal series will be played Friday and Sunday in Denver.

Houston took a 53-43 lead at halftime, then scored the first eight points of the third period.

"It was no contest tonight," Denver Coach Doug Moe said. "We had no offense. We stunk up the place. We had no chance tonight."