The Washington Bullets' pleasure in beating the Philadelphia 76ers, 118-106, last night at Capital Centre likely was increased by the knowledge that injured center Jeff Ruland might be available when they begin the first-round, best-of-five playoff series Wednesday in Philadelphia.

Ruland, inactive since Feb. 1 because of a strained right shoulder, received an injection of pain-killers last Monday. By last night, the soreness had abated enough that Bullets Coach Gene Shue said the center would practice with the team Monday.

For that to be possible, Ruland would have to be included on Washington's 12-man playoff roster, which is due the NBA office by midnight tonight.

Last night, even without Ruland, the Bullets had more than enough firepower. Leading the way was Gus Williams with 33 points. Jeff Malone had 26 for the Bullets and Cliff Robinson 20. Moses Malone led the Sixers with 25 points.

"This was just a great game for us, and very significant," said Shue. "First of all, we wanted to finish with a win and secondly we wanted to be playing well. We certainly did both of those things tonight."

For the past week the Bullets have played better basketball than at any time since Ruland went out of the lineup, winning three of five games. In the last two, yesterday's victory and a 102-96 loss to Detroit Friday night, Williams started off well.

Last night against Philadelphia, he hit five of his first six field goal attempts, scoring 12 points in the first quarter and 22 at the half, including a 58-foot three-point field goal at the end of the second quarter.

"Gus had been struggling with his outside shot but he shot well last night and came back again tonight and that's something that we have to have," said Shue. "It's very . . . important for us."

According to Williams, the improved marksmanship isn't the result of any technical adjustments to his shot. "I'm not doing anything differently, the ball is just going in now," he said.

The remarkable thing about last night's game for the Bullets was that Williams was not the only one having that happen. "Over the course of the game, different players would pick us up," said Shue. "That's something that you look for."

The best example of that came in the fourth quarter. Trailing by four, 87-83, entering the final 12 minutes, Philadelphia tied the game. But then Washington took control, sandwiching two runs of eight points around a lone layup by Maurice Cheeks.

In that spurt, five Bullets scored, including four points by Tom McMillen. Darren Daye scored 10 points in the quarter and Rick Mahorn, playing much of the time with five fouls, got 10 of his 13 rebounds in the period.

Philadelphia Coach Billy Cunningham was ejected with 4:54 left after dashing onto the court to argue that a foul should be called against the Bullets.

Just how important yesterday's contest will be next Wednesday was open to interpretation. The Sixers played without starting guard Andrew Toney, currently on the injured list with a sprained ankle. "With him in the game we have more offensive punch and an outside threat," said Cheeks.

According to Julius Erving, "Their winning tonight in front of a big crowd (18,306) probably gets them and their fans excited about their prospects in the playoffs."

As for his team, which has lost eight of 14 games, Erving said, "Nothing is given this year, but now we get to have a little rest and we'll come back together as a team. I would be ashamed for us not to reach our full potential."

Of course, with Ruland back, the Bullets might be in good position to come back together as a team and reach their full potential.