At the start of the Washington Bullets' five-game winning streak, center Jeff Ruland was asked how the team knew when to run the fast break and when to go into its set offense.

"It's a very simple process," he said, only half joking. "Gus (Williams) is the only one of us allowed to run, so if he's out on the break we're running. If he's not, we're walking."

The pointed comment, coming on the heels of a four-game losing streak that directly preceded the Bullets' turnaround, might have been the first sign of discontent with the team's new upbeat image. But the five games that followed have seen nearly everyone, including the 6-foot-10, 260-pound Ruland, running a fast break that has been close to blistering.

At the same time, the Bullets haven't forgotten the bruising inside power game that has been their staple in recent years. The combination has allowed them to virtually control their last five games. Beginning tonight, however, that control will be put to the test.

A game in Philadelphia against the 76ers, 7-2 and 1 1/2 games ahead of the Bullets in the Atlantic Division standings, is the first in a stretch of four games in five nights. Other opponents this week include the defending NBA champion Celtics in Boston Friday and the Detroit Pistons, a consensus choice as the league's next elite team, the following night at Capital Centre. Between the Philadelphia and Boston games, the Kansas City Kings make their only Capital Centre appearance of the regular season, on Wednesday night.

"We're confident now, the players are more alive and pleased with themselves, as well they should be," said Bullets Coach Gene Shue. "These upcoming games will give us a better idea of where we're going or how far we have to go."

Last Thursday and Saturday, the Chicago Bulls, another team with aspirations of moving to the top, played Boston and Philadelphia. They also looked upon the games as a measuring stick of how they compared to those two. Although both games were played before sellout crowds at Chicago Stadium, Boston won by 20 points and Philadelphia by nine.

In neither game, however, did the Bulls show the offensive mixture presented by the Bullets the past two weeks. Although Williams has set the pace for the fast break, Shue argues that the team actually does a better job of running when players such as Darren Daye, Jeff Malone and Cliff Robinson enter the lineup.

"The way it's been working lately, we've sort of found our own tempo out on the floor," Shue said. "I'm very pleased with that. I might call some plays early, but if they're going good I'd just as soon let them do things themselves."

That could be a problem against Philadelphia and Boston, although the Bullets pretty much had things their way in a 112-95 rout of the Celtics Nov. 10 in Landover. "The good teams are capable of shutting down your fast break, so you have to go to your set offense more," Shue said. "It will be interesting to see if we're as consistent as we have been in the last five games."

One could almost set a clock to the patterns played by the Bullets over the course of their winning streak. They generally have fallen behind early in the first quarter, then closed out the period with a rush. The momentum built by the starters is picked up by the speeding substitutes in the second period as the Bullets take control of the game.

Following intermission, the starters go back onto the floor as if determined not to be outdone by their replacements. The result is another strong run that effectively puts the game on ice.

Said Shue, "If it happens that way it's a good pattern to be in, but I'm not certain it will always be like that."

Tonight seems the perfect opportunity to find out just how long it will continue.