hen the success story of the Washington Bullets this season is written, one of main reasons given for their surprising record will be their ability to win on the road.

The streaking Bullets completed a two-game sweep of the Midwest tonight by running past Chicago, 114-98, for their 20th victory in 39 road games. They started the trip by beating Indiana.

The victory, coupled with New Jersey's 106-103 loss at Boston, moved the Bullets into sole possession of third place in the Atlantic Division. As it stands now, they would have the home-court advantage in a best-of-three series with the fourth-place team. One more victory or loss by Detroit and a playoff berth will be assured.

For the Bullets, the only sour note in an evening highlighted by Spencer Haywood's 25-point performance was Kevin Grevey's minor injury. The jump-shooting guard pulled a muscle high in his right leg in the third quarter and was limping slightly after the game.

"I tried to keep playing on it, but it only got worse," he said. "I don't know how it will be tomorrow night."

The Bullets will try to extend their latest winning streak to four games Saturday night (8:05, WTOP-1500) when they play surging Milwaukee at Capital Centre in a game that previously was scheduled for the afternoon.

The Bucks, playing without the injured Quinn Bucker, Junior Bridgeman and Brian Winters, defeated Detroit, 118-100, tonight for their seventh straight victory. They have won all four games against the Bullets this season.

"We're as ready as we'll ever be for the Bucks, if Grevey is all right," Coach Gene Shue said. "This was the second best game our offense has played. We were executing, getting good shots and making them.

"There are several ways we can win. Our defense has been good lately, but I wanted us to run our plays better, and tonight we did."

Defense, of course, has been one of major ingredients of the Bullets' success this season. In the last five games, they've yielded 472 points, an average of 94.4 a game.

The Bulls' plan was to get the Bullets involved in a running game and then use their quickness to advantage in the back court. The Bullets, however, beat the Bulls at their own game, breaking away for easy shots and making 52 percent in the first half when they took an eight-point lead they never lost.

"This was a good tuneup for Milwaukee," Grevey said. "We were able to get any shot we wanted. We ran our offense well and they, well, they're out of the playoffs and they sort of gave up after a while."

Haywood has been strugging lately and made only three of 15 shots at Indiana. He had a talk with Shue today and said it helped him relax and regain his shooting touch.

"Coach hasn't steered me wrong yet," the 31-year-old forward said. "He told me I was trying too hard on offense, that I should relax, play good defense and the shots would come."

Haywood made five of six shots in the second half and 11 of 18 overall as he came within two points of his season's high despite playing only 28 minutes.

Rick Mahorn, who had a career-high 17 rebounds in Indiana, contributed 16 points, five rebounds and four blocked shots. Jeff Ruland led all rebounders with 16 and scored 15 points. He made all seven of his foul shots.

After losing a 23-16 lead when the Bulls tied the game at 24, the Bullets moved in front, 32-16, in the opening minutes of the second quarter. Grevey had nine of his 14 points in the first quarter as Frank Johnson directed the fast break.

The Bullets increased their lead to 49-39 late in the second period as Don Collins entered and scored six quick points. They couldn't get their advantage to more than 13 throughout the third period, but when Artis Gilmore and David Greenwood went to the bench in foul trouble, the Bulls didn't have the rebounding strength to keep their running game going.

"Every time they made a run at us, we had an answer," Shue said. "Our defense never let them get a streak going."

Gilmore scored 17 points and blocked six shots, but his teammates obviously played like a team that has been eliminated from the playoffs and is counting the days until a disappointing season ends.