The Washington Bullets slowed the Philadelphia 76ers to a walk last night and then outmuscled them inside, coming away with their most significant victory of the season, 100-97, before a sellout Capital Centre crowd of 19,035.

The victory was the Bullets' first in eight games and two years over the 76ers, but Washington did have a significant loss: point guard Frank Johnson. He suffered a chipped bone in the right elbow when he fell after drawing a charging foul on Moses Malone at 5:56 of the third period.

After looking at X-rays, Stephen Haas, the team physician, said Johnson would be out for three to four weeks, but that he would reevaluate his condition Monday.

The outcome wasn't decided until Don Collins made three free throws in the final 10 seconds, but it was still a case of the Bullets being one step up on the 76ers all night.

The victory was the Bullets 10th in 13 games and improved them to 13-11 overall. The 76ers, who entered the game with the best record in the National Basketball Association, lost for the fifth time in 25 games.

The Bullets won this game where Shue likes to win them--on defense and on the boards. The 76ers are the league's leading rebounding team, but the Bullets outrebounded them, 53-46. The Bullets also had 21 offensive rebounds, which they turned into 24 points.

Center Rick Mahorn and forward Spencer Haywood each had 11 rebounds and Mahorn had eight blocked shots, equalling a career high.

The Bullets, who led most of the game, had an 87-80 after lead Mahorn's jumper with 5:45 remaining. A layup by Maurice Cheeks and a twisting move in the lane by Julius Erving cut the lead to 91-89 with 3:30 left. The 76ers got two more shots however, missing both.

The Bullets were leading, 96-93, with a minute left when Haywood blocked a shot by Bobby Jones. Philadelphia Coach Billy Cunningham was so upset, and so vocal in expressing his displeasure, that he was called for a technical foul by official Terry Durham.

Ballard, who finished with 15 points, made the ensuing foul shot.

Malone made two free throws with 38 seconds left to cut the lead to 97-95, but Collins rebounded after Bryan Warrick missed a long jumper as the 24-second clock was running down. Collins was fouled by Malone, and made two free throws for a 99-95 lead with 10 seconds left.

Malone was fouled by Mahorn with six seconds remaining and made two free throws. Philadelphia was forced to foul and Erving grabbed Collins with three seconds left. Collins made one of two shots and the 76ers didn't get off another shot.

Collins finished with 15 points, six rebounds and four assists.

"We've been down this road a lot of times with the 76ers," said Bullets Coach Gene Shue, "but we usually lose. We'd lost to them seven times in a row and we felt it was time to try something different. We changed our matchups and I think that was very significant."

The Bullets put Mahorn on Erving, who is four inches shorter. Ruland guarded Malone and Ballard, a small forward, guarded power forward Mark Iavaroni.

Malone did score 25 points, but didn't dominate.

Mahorn held Erving to 20 by keeping him outside. And he flattened the 76ers with some vicious, yet legal, picks.

In the first period, he leveled Cheeks. The guard had to be helped to the dressing room and didn't reappear until the second quarter was half over.

In the third period, Andrew Toney ran into Mahorn and he, too, had to be helped off the court. He was to be X-rayed back in Philadelphia today to determine if he had a separated right shoulder.

Cunningham was enraged.

"I think at some point he (Mahorn) is going to get his," said Cunningham. "You play this game hard, but you don't go out looking to hurt people. I hope the league does something about it at some point before someone gets maimed or seriously hospitalized."

Ruland had his right hand examined after the game, but X-rays showed no fracture.