A casual conversation between Gene Shue and Kevin Porter three days ago resulted in Porter suggesting that rookie Wes Matthews replace him in the Bullets' starting lineup.

The coach took up Porter and the move paid off with a resounding 109-96 Washington victory over the Cleveland Cavaliers before 5,118 last night at Capital Centre.

The triumph was dampened by an injury to center Wes Unseld. He pulled a groin muscle as he tried to shoot a layup over Cleveland's Kenny Carr late in the third period. Carr was called for goaltending on the play, and Unseld came up limping. He tried to continue, but one minute into the final quarter took himself out and went to the dressing room.

Trainer John Lally said it would be36 hours before the extent of the injury was known.

Matthews was brilliant. He played all 48 minutes, scored 20 points on nine of 13 shooting and had 11 assists.More impressive to Shue, however, was that he had only two turnovers and two fouls.

Going into the game, Matthews had lost the ball a team high 18 times. He said he realized he had to make changes and, as a result, toned down his usually flamboyant game.

"I just recognized situations better," he said. "I'm not trying to be so fancy. I was more controlled. I slowed myself down, was patient and concentrated on what I was doing."

Shue said he had not intended to play Matthews the whole game "but as long as he was playing as well as he wasI was going to leave him in."

Shue added that Matthews would continue to start, although, the coach said, Porter still is valuable to the team.

"I expect Kevin to come off the bench and contribute," Shue said. "What I'm trying to do is get the right combinations out on the floor and that's difficult sometimes.

"I think West is a little more settled if he starts, and if Kevin comes in with shooters like Greg (Ballard) and Mitch (Kupchak) he'll do well, too."

Porter had not been doing that badly. He is averaging 12 points a game and is sixth in the NBA in assists with a 6.2 average.

"I was just talking to Kevin about something else and he suggested that it might be a good idea to start Wes," Shue said. "I thought about it and decided to go with it."

The victory snapped a four-game losing streak and for the first time this season the offense ran smoothly. ElvinHayes got the ball where he wanted it and responded with a season high 27 points as he made 12 of 22 shots.

Bob Dandridge added 20 points, six assists and three steals.

John Williamson scored 10 points, but surprised onlookers with eight assists and two steals and an overally solid defense.

The Bullets next play Friday in Chicago against the Bulls.

The Cavaliers continued to be a two-man team, with forward Mike Mitchell getting 32 points and guard Randy Smith 23 and 13 assists.

The game was close most of the way until the Bullets pulled away in the fourth period. They went into the quarter with a 79-76 advantage and midway through ran off a 10-0 spurt. The Cavaliers, who played only seven men, wilted.

Dandridge started the run with two baseline jump shots. Hayes followed with a fast break basket off a slick pass from Matthews, then Williamson fed Dandridge and Rick Mahorn with nice passes on back-to-back fast breaks.

Mahorn, playing more because of Unseld's injury, made four of six shots, had five rebounds and blocked a shot in 11 minutes, all in the final quarter.

"It was about time we took control of a game," Shue said.

The Bullets also shot better than 50 percent (52) for the first time this season.