Julius Erving scored a season-high 31 points and Terry Catledge had 27 last night to lead the Philadelphia 76ers to their fifth straight victory, a 116-112 decision over the Detroit Pistons, at the Spectrum.

Philadelphia used a 24-6 third-quarter run to take control of the game, and held off a late rally.

Philadelphia led, 112-103, on Catledge's basket before Detroit scored nine of the next 11 points, to come within 114-112 with 15 seconds left after Earl Cureton hit one of two free throws. But Erving's two free throws with 12 seconds to play sealed the outcome.

Vinnie Johnson had 23 points to lead Detroit.

In New York yesterday, the NBA announced it had fined Sedale Threatt of the 76ers $2,000 and Danny Ainge of the Boston Celtics $1,000 for their roles in an altercation during their game Sunday.

Six others, including 76ers Coach Matt Guokas, each drew $500 fines.

Rod Thorn, the league's vice president of operations, said in a statement that Ainge received the fine for shoving Threatt and Threatt was fined for throwing a punch.

Guokas was fined for "coming onto the court as other than a peacemaker" and Clemon Johnson of the 76ers was fined for inflammatory remarks, the statement said.

*Celtics 126, Bucks 114: Larry Bird scored 26 points and Bill Walton added a season-high 22, powering Boston in Milwaukee in a matchup of divisional champions.

The triumph was the fifth in a row for the Celtics over Milwaukee and improved Boston's record to 65-14. Milwaukee is 55-25.

Terry Cummings led the Bucks with 22 points and Moncrief had 18 as he returned after sitting out two games with a sore right foot.

*Hawks 131, Bulls 118: Dominique Wilkins scored 37 points, including 12 in the fourth quarter, to lead Atlanta over Chicago in the Omni.

The loss cut Chicago's lead to one-half game over Cleveland for the last playoff spot in the Eastern Conference. The Bulls have one game to play and the Cavaliers two.

Michael Jordan led the Bulls with 30 points in 33 minutes on the floor. He is recovering from a broken foot, and the club is limiting his playing time.

The Hawks led by 14 points after three quarters, stretched it to 22, and the Bulls could come no closer than eight points in the final quarter.

Randy Wittman had 23 points for the Hawks and Wilkins led all rebounders with 13.

*Rockets 109, SuperSonics 95: Reserve guard Mitchell Wiggins scored a season-high 22 points and Robert Reid had 18 as Houston won at home, eliminating Seattle from playoff contention.

Seattle's Tom Chambers had a season-high 32 points.

The SuperSonics scored only two points in the first eight minutes of the third period. By then, the Rockets had a 68-58 lead. The Rockets scored the first 10 points of the fourth quarter.

*Warriors 129, Mavericks 115: Despite playing without Chris Mullin, Purvis Short and Joe Barry Carroll, Golden State used a balanced scoring attack led by Eric (Sleepy) Floyd to beat Dallas in Oakland, Calif.

Floyd led six teammates in double figures with a game-high 29 points; Terry Teagle scored 23.

Guard Derek Harper led Dallas with 23 points.

*Lakers 120, Trail Blazers 114: Kareem Abdul-Jabbar sank five consecutive skyhooks in the fourth quarter and scored a game-high 26 points to lead Los Angeles over visiting Portland. It was the sixth straight victory by the Lakers over the Trail Blazers this year, the first season sweep by Los Angeles over Portland since the 1972-73 season.

The Blazers trailed most of the game but reserve guards Terry Porter and Jim Paxson led a comeback that tied the score at 86 two minutes into the fourth quarter.

Portland held the lead until about four minutes before the final whistle. That's when Michael Cooper put the Lakers ahead, 101-100, on a breakaway layin. Then Byron Scott scored on another breakaway to give the Lakers a 103-100 lead Portland could not overcome.