Dr. J and Dr. Dunk were mortal men yesterday but Philadelphia reserves Bobby Jones, Steve Mix and Henry Bibby put on a dazzling fourth quarter to lead the 76ers over the Bullets, 95-92.

Jones, Mix and Bibby accounted for all 25 of Philadelphia's last-quarter points, most of them coming out scintillating fast-break baskets or from the foul line.

A Christmas Day crowd of 18,184 and a national television audience, except for a blacked -out Washington area, saw Philadelphia's third straight victory over the Bullets this season and the second one at Capital Centre. The streaking 76ers, who have the second best record (26-10) in the National Basketball Association, behind Boston (27-8), have won 13 of their last 16 games.

The Bullets made it exciting at the end by scoring eight of the game's final nine points and then getting the ball back with five seconds to play and a chance to tie the score with a three-point shot.

Kevin Grevey's 35-footer, from beyond the top of the key with one second left, missed.

The 76ers turned the ball over three times and missed two shots in five possessions, while the Bullets were scoring four times in five possessions.

Greg Ballard's basket following an offensive rebound and another to complete a fast break hadcut the lead to 94-92 with 18 seconds left.

The Bullets were forced to foul to try and get the ball back and Jim Cleamons fouled Billy with five seconds left. Bibby made one of two free throws, forcing the Bullets to try a three-point shot at the end.

"That was the best shot we could get," said Grevey. "They were giving us a two-point shot, but not any three-pointers."

The Bullets had a better chance for a three-point shot two second earlier when Larry Wright had the ball in the corner, a step beyond the three-point line. Wright looked down to make sure he was behind the three-point line before he shot and that gave Bibby enough time to grab him for a non-shooting foul. That used up two seconds and after the Bullets took the ball out of bounds the only, thing they had time for was Grevey's desperation heave.

Assistant Coach Bernie Bickerstaffdirected the Bullets the entire second half because Dick Motta was ejected at halftime. Motta had one technical foul called on him near the end of the second quarter and drew his second, and the ejection, when he continued complaining to official Dick Bavetta after the half ended.

"We were just taking off and running," Jones said of the 76ers fourth-quarter effort. "We were aware that they (the Bullets) were tired, so we gambled a lot on defense and took off as soon as they put up a shot."

Jones scored 12 of his 18 points in the final period, Mix half of his 12 and Bibby five of his 15. Julius Erving, Dr. J., scored 17 and Darryl Dawkins, dr. Dunk, added 13.

The 76ers went into the final period down, 71-70, with Erving resting on the bench.

A baseline jumper by Roger Phegley gave the Bullets a 77-74 lead with 10 minutes left, but then the 76ers exploded. They scored nine straight points, seven off the fast break, to take an 83-77 lead with 7:26 to play.

Jones started that Philadelphia streak with a three-point play off the break and, after a Bullet miss, Billy scored on another fast break. The Bullets missed again on their next possession and Jones scored on a left-handed driving layup around Mitch Kupchak.

Two more Bullet misses set the stage for another Jones fast-break stuff and the panting Bullets were forced to call time out.

Washington appeared to get back into the game after Ballard scored on a long jumper that cut the 76ers' lead to 87-83 with 5:37 left.

Philadelphia went right back to fast breaking, though, and outscored the Bullets, 7-1, for a 94-84 lead with 2:47 to play. Jones had a three-point play off a driving dunk and another fast-break dunk in that spurt.

The defeat was tough for the Bullets for a number of reasons. To begin with, Ballard, playing for the injured Bob Dandridge, more than offset Erving. Both played 27 minutes, but Ballard outscored the Doctor, 19-17, and outrebounded him, 8-7. Ballard's defense forced Erving into six-of-17 shooting.

The other Philadelphia star, Dawkins, added 14 rebounds to his 13 points, and blocked four shots. He had only one monster dunk and left the Centre backboards intact.

But Mix, Bibby and Jones did in the Bullets who were led by Elvin Hayes' 29 points and 12 rebounds.

"The difference was the bench," said Ballard. "It looks like (the reserves) could be better than their starters.

I think it would have really helped us if I could have come off the bench because it would have at least neutralized their bench a little bit."

The 76ers showed they are more than just a free-wheeling, fast-breaking group that loves to dunk. Their shots weren't falling in the first half, so they stayed in the game with their defense.

In the first quarter they made only seven of 25 shots and for the half, they shot 33 percent.

"We didn't shoot the ball well, but we kept our intensity defensively," said 76er Coach Billy Cunningham.

"Our offense wasn't working so we went to traps on defense to keep us in the game."

Because of their defense the 76ers were down by only three points, 50-47, at intermission.

"The only place where they really hurt us was on the offensive boards," said Cunningham. "That's where Washington always hurts you."

The Bullets outrebounded the 76ers, 57-47, including 21-8 off the offensive boards.

The 76ers blocked 16 Bullet shots, however, and many of those were on those second attempts after a Bullet got an offensive rebound.

"This isn't the only game this year we've won with our bench," said Mix. "This is a self-sacrificing team now, instead of one where everyone tries to do it by himself."

Washington's next game is tonight at New Jersey.