Winning is a good coverup. Take Mitch Kupchak of the Washington Bullets, for instance.

A week ago, in warming up for the team's home game against the Boston Celtics, Kupchak felt a strange sensation in his right wrist, the one he had broken in three places in his youth and which team physician Stan Lavine has told him did not heal properly. He cannot flex the wrist.

But, even with starting center Wes Unseld sidelined with bruised rib cartilage, the Bullets defeated the Celtics, then the Phoenix Suns Wednesday, giving Washington eight straight road victories and 16 wins in their past 18 games.

The fact that Kupchak had become a one-handed player and was not up to his usual high-octane performance was overlooked because the defending NBA champtions were winning.

But, in the first half against the Lakers Friday night, Kupchak managed just two points and three rebounds and the Bullets found them- selves 10 points down at intermission in a 127-115 loss.

So, the bullets left early this morning for Portland and tonight's final game of his 1-1 road trip hurting at center.

"It's the same thing that happened two years ago," Kupchak said. "I broke it in three places once. The doctor said it didn't heal correctly, and I have trouble with it now and then. I can't bend it. But it'll be all right."

As Elvin Hayes put it, "We beat ourselves more than they (the Lakers) beat us, really."

A major factor in the defeat, besides a strong game from Laker center Kareem Abdul-Jabbar, forward Don Ford's 22 points in his first start of the season and guard Norm Nixon's 20 points, 12 assists and seven steals, was that the Laker reserves outplayed Washington's substitutes.

"We missed Wes a little bit tonight," Coach Dick Motta said ofhis center who did not make the trip. "It hurts when we have to startour bench. We can't usa a double pace on Kareem as we normally would with Wes and Mitch.

"Wes comes and lays on him," Motta added, meaning that Unseld uses a lot of muscle in combating jabbar. "Then Mitch comes in and gives another look."

The Lakers received big efforts from reserves Dave Robisch (13 points) and Kenny Carr (10 points, nine rebounds) while Bullet guard Charles Johnson and forward Greg Ballard played well below their normal standards.

The Lakers, since star forward Adrian Dantley was injured, had won only five of 11 games. So Coach Jerry West, in an effort to get more offense, started Ford instead of Carr at Dantley's position and Lou Hudson at guard in place of Jimmy Price.

Ford and Hudson scored 38 points and Carr played well coming off the bench.

The Bullets were the better team in the early going of a flat game. West had Jamaal Wilkes guarding Hayes with Ford on Bobby Dandridge at the forwards.

Hayes burned the smaller Wilkes for 11 points in less than nine minutes. Then turnovers started to plague the Bullets. They committed 14 in the first half, including what Motta called "three flat passes when we had layups" and the Lakers had a 64-54 half-time lead.

The key was a 13-2 surge when the Bullets missed four shots and committed three turnoversas Jabbar became dominant, blocking shots and scoring nearly as he pleased. He had 14 of his 22 points in the quarter.

Spotting the Lakers 10 points at home, where they lead the league with a 15-3 record, is usually imposible to obercome. It was Friday night.

Dandridge and Kevin Grevy each scored 24 points for Washington. Hayes had 20, 17 in the first half.