Comedian Rodney Dangerfield says his wife is so ugly . . .so ugly . . .that when you look up "ugly" in the dictionary, there's her picture. They could take out the poor lady now and put in a team portrait of the Bullets. One look at those guys last night would turn you to stone. If basketball were a beauty contest, those Bullets couldn't whip Phyllis Diller.

With about three minutes to go in the third quarter last night, the 19,035 paying customers delivered a passionate critique of the Bullets they have come to love during two wonderful seasons.

They booed like crazy.

With good reason.

As basketball teams go, the Bullets are redwoods and the San Antonio Spurs are saplings. If the Redskins had specimens built like Elvin Hayes and Wes Unseld, Tony Dorsett might oversleep all season. So when the Bullets found out they would play the Spurs for the NBA Eastern Conference championship, everyone assumed the world champions would beat up on the Spurs and take every rebound north of the Alamo.

So with about three minutes to go in the last quarter, what happens?

The Spurs get six shots in one trip down court.

Six shots! The tender branches of the tiny saplings knocked those mighty redwoods all over the lot. Five times the Spurs missed shots, and every time they got the rebound. You'd have thought Hayes and Unseld had overslept.

When Gervin would up this six-shooter trip by making a 12-footer, it gave the Spurs a 75-69 lead. And the paying customers booed the world champions on their home court, as embarrassing a development as any team can suffer.

Almost.

The most embarrassing thing, of course, would be if the world champions, booed by the folks who care most, then proceeded to play even worse.

The Bullets did that, too.

For the first 33 minutes, the Bullets had played poorly, yet trailed only 71-69. By game's end, surely, the big, bad Bullets would wear down these 98 pound weaklings whom they had beaten three times in four games this season. That's the way it went in last year's playoffs, when the San Antonio guards couldn't beat the Bullets in six games.

Who knows why the Bullets died in that third quarter? Put in a call to Perry Mason. Where is Sherlock Holmes when we need him? From that 71-69 score, the Spurs outscored the Bullets, 15-4, in four minutes and 19 seconds to take an 86-75 lead into the fourth quarter.

Hoop detectives trying to solve the mystery will find several clues.

For one, Elvin Hayes was a missing person.

For another, the Bullets' guards were throwing up so many bricks that they should join a masons' union.

Hayes' disappearance-we would call it a kidnaping, but no one delivered a ransom note-was particularly baffling.

Hayes is a magnificient player who can score points against anybody. At halftime he had 12 points on 6-of-14 shooting. But when the Bullets had fallen behind by 15, at 100-85 with six minutes to play, Hayes had scored only two more shots.

That's ridiculous.

Whether it was Hayes' fault for not moving to a spot where he could get the ball, or whether the Bullets in their incredible chaos forgot that they had on their side one of the NBA's best scorers ever, perhaps only Mickey Spillane could discover.

But if the Spurs could have one wish, it would be that Hayes shoot only twice in the first 18 minutes of the half that matters most.

If they could have two wishes, it would be that the Bullets' guards keep on shooting.

With a hoop the size of Orson Welles' belt, the Bullets' guards might have shot 50 percent last night. That is a gentle assessment of their ineptitude. Of 39 shots, the Bullets' five guards made 10.

Tom Henderson shot an air ball from five feet on a layup. Phil Chenie rwas three for 13, Kevin Grevey one for nine. One melancholy vignette tells the story: Henderson, trying another layup, had it blocked. In the process, he was bumped to the floor.Teammate Greg Ballard grabbed the rebound, but came down on Henderson's stomach and fell himself. Traveling was called.

So ineffective were the Bullets guards, both offensively and defensively, that someone asked Dick Motta if the coach considered using Bobby Dandridge in the back court as he did in last year's playoff against the Spurs. Motta didn't like the question.

"I have one assistant now," he said angrily. "Maybe you need the job, huh?"

If the Bullets' guards resembled refugees from YMCA noon hour, the Spurs' guards looked like they had stepped out of the Hall of Fame. This was no contest, this was Ann-Margret against Bella Abzug.

George Gervin, James Silas and Mike Gale of the Spurs made 29 of their 50 shots. They outscored the Bullets' Futile Five, 68 to 26. No one expects a team at this level to win an important seven-game series on play by its guards-the percentages favor the redwoods when the wind blows the strongest-but if any team can do it, it is San Antonio.v. hy? Look at this . . .

The Spurs led, 98-85, when Gervin drove down the left side of the lane. No, not "drove." He glided. No hurry in the Iceman. Elvin Hayes is waiting to block the layup. So they are in the air together, and Gervin, instead of moving toward Hayes, leans away from him.

And while leaning back, Gervin rolls the ball off his fingers, sort of flipping it into the air. He puts it up high, the way you'd throw a penny at one of those glass dishes in a carnival trying to win a teddy bear. For Tom Henderson, this trick produces air balls. For Gervin, the ball did his bidding. Two points.

"A hangin' leaner!" said an awed witness.

"I don't name 'em," said Gervin. "I just be hopin' they go in."

Maybe, as some of the Bullets have suggested before, the world champions don't like to do anything the easy way. By losing the first game of a seven-game series at home, they have given up the home-court advantage.

More important, the way the Spurs created the 21-point victory-by outscoring the world champions 47-28 in the last 16 minutes on their court-may have been proof the Bullets have a fatal flaw in the continuing slump of the guards.

Stay tuned.