The Washington Bullets lost their starting back court through injury last night, when they lost the National Basketball Association championship, 97-93, to the Seattle SuperSonics.

A stunned sellout crowd of 19,035 at Capital Centre watched the Sonics ride a 12-0 spurt midway through the last half to their first league title, avening a final-round loss to Washington last season.

And the Sonics did it in most impressive fashion. After losing the series opener here, they won four straight fending off fierce Bullet challenges in the last two contests.

But even great Washington intensity last night could not overcome injuries to Kevin Grevey and Tom Henderson by the time the contest was 25 minutes old.

"When Kevin and Tom went down with injuries," said Bullet Coach Dick Motta, "maybe it only delayed the inevitable. We had a tough time in this series. I don't like making excuses. Seattle played real well, they responded when they had to."

Grevey pulled his right hamstring three minutes into the contest. Henderson twisted his ankle in the first minute of the third period. Neither returned, cutting the already struggling Bullet backcourt to three players.

That wasn't enough against Seattle's talented Dennis Johnson and Gus Williams. The two guards, who time after time frustrated Washington throughout the series, capped off the round with magnificient performances.

Johnson, named the series' most valuable player, scored 21 points and was strong down the stretch when the Bullets made a last desperate rally.

Williams finished with 23 points after a two-for-nine first half. He scored four of Seattle's last five points, two on free throw with 12 seconds remaining that wrapped up the championship.

Seattle's third consistent offensive weapon, Jack Sikma, was limited to 12 points but his 17 rebounds enabled the Sonics to again neutralize Washington on the boards, as they had all round.

Washington was striving to become the first team in a decade to repeat as champions. But after compiling the league's best regular season record, the Bullets struggled unsuccessfully throughout the playoffs to regain their championshipform.

They defeated Atlanta, 4-3, in the Eastern Conference semifinal round and had to rally from a 3-1 deficit in the conference championship to overcome San Antonio,becoming the third team in NBA history to overcome such a handicap.

But Seattle proved far more talented than either the Hawks or the Spurs. Once Washington lost Game 2 - and the home-court advantage - it became only a matter of time before the Sonics' stronger back court wrapped up the title.

Knowing that they faced a sudden death, the Bullets began this game as if they would run away with the victory by halftime.

With Elvin Hayes scoring 20 of his 29 points,they were up, 51-43, at intermission after leading by 11 earlier in the half. Their 56 percent shooting was their best since the opening game of the series and it became even more important when Seattle struggled with 38 percent accuracy.

But Sikma said the Sonics decided in the locker room "to hold the ball an extra second or two, just to look for the open man and then get it to him."

That tactic began working just before the end of the third period, when the Bullets were sitting on what looked like a comfortable 69-60 lead.

In the next five minutes, Washington didn't score, while the Sonics ripped off that string of 12 unanswered shots in that stretch, just when the Bullets' shooting betrayed them.

By the time Charles Johnson broke the scoreless string. Seattle was ahead for the first time, 72-69. From then on, it became a contest against the clock, the struggling Bullets attempting to rally despite their poor shooting.

Guard Fred Brown, who had been silent most of the series, continually hurt Washington with his jump shooting when the Sonics pulled away to a 85-77 advantage with 3:40 left.

Brown scored eight points, and sanka couple of floating one-handers, to get Seattle untracked. Then Dennis Johnson, with nine points, all but finished off Washington.

Larry Wright's jumper and two foul shots by Bob Dandridge, who finished with 20 points, seven assists and nine rebounds, had Washington within three with 2:55 to go.

Williams, who scored nine points in the third period, replaced Brown and popped in a jumper. Hayes missed but Greg Ballard grabbed the rebound and eluded Sikma for a reverse layup.

When Sikma made only one of two free throws and Wright answered with an 18-footer, the margin was two. But Williams used a Sikma screen to elude Wright and bank in a shot from a tough drive down the right side.

After a timeout, Wes Unseld made good from the top of the key and again Seattle was ahead by only a basket, 93-91. Williams couldn't get off a shot on a drive, but passed off to Johnson, whose awkward off-balance attempt went in and it was 95-91 with 42 seconds left.

Wright delighted the fans with a pair of free throws four seconds later. They stood and roared and yelled "defense, defense," asking their team to dig one last time and pull out a miracle.

It wasn't to be. Sikma was double-teamed in the corner and had to pass to Johnson, whose jumper wasn't close.the Rebound went off Unseld's hands, then the Sikma's, then Hayes' and ended in the possession of John Johnson.

With 12 seconds remaining, the Bullets had to foul. Phil Chenier bumped Williams and the Sonic guard made both foul shots to set off a celebration on the Seattle Bench.

"Last year we didn't know to expect in this series but we came in with our eyes open this time" said Dennis Johnson. "We did everything we had to do to win."

Johnson, a 6-foot-5, agile athlete with great leaping ability and quickness, keyed a Seattle defense that the major weapon against Washington throughout the series. The Sonics' ability to double-team Hayes and Dandridge inside, while the Bullets guards failed repeatedly to hit open and shots finally proved too much for Washington to overcome.

Last night, Seattle's guards accounted for 58 points on 24-of-50 shooting. The Bullets answered with 27 backcourt points on 11-of-29 accuracy, getting only two points from Grevey and Henderson.

This also was a game in which Seattle, not the veteran Bullets, held up better under fourth-quarter pressure. The Sonics were uncanny down the stretch, making 12 of their last 20 shots, while Washington opened the last quarter by missing nine of 12.

Nor could the Bullets take advantage of their free throws. They missed five in a row midway through the second half and only 15 of 23 the game.

Seattle also shut down the Dandridge just when the Bullet forward wanted to take charge. Switched to guard to start the last 12 minutes. Dandruidge was held to three free throws by Dennis Johnson before fouling out with 1:29 left.

"I didn't have any feeling of impending doom in the fourth quarter," said Bullet General Manager Bob Ferry, "but there is a certain amount of fate in the playoffs and when those shots of theirs started falling, I began thinking fate was on their side this time."

Seattle also had superior quickness and intensity on their side.

"I think they got all the loose balls," said Grevey. "Their defense was strong and their offense was more crisp.

"They really, really wanted it. They were hungry. Not that we weren't, but they just seemed to be able to dig deeper."

Grevey, who had been bothered by a hamstring pull since January, was hurt driving in for a fast-break layup. He was bumped by Dennis Johnson and fell to the floor. When he got up, he was clutching his right thigh. He stayed in for his free throws but singled to the bench to come out.

Henderson's ankle sprain occurred away from the ball. He stepped on Dennis Johnson's foot under the basket and fell out of bounds. He hoped to play the fourth quarter but the ankle hurt too much.

Ironically, this could be the last game in Bullet uniforms for Grevey and Henderson, both free agents.

They also could be the last game in Bullet uniforms for Grevey and Henderson, both free agents.

They also could be part of a fullscale change in the Washington backcourt. After the inconsistent play of the guards in the playoffs, team officials probably will be tempted to make at least some personnel changes before next season. CAPTION: Picture 1, Injured guards Kevin Grevey, in street clothes, and Tom Henderson, with ice pack, watch end of game with Dave Corzine. By Richard Darcey - The Washington Post; Picture 2, Celebrating Sonics, from left, are the assistant coach, Les Habegger, Coach Lenny Wilkens, captain Fred Brown and Dennis Johnson. By Richard Darcey - The Washington Post