From the euphoria of Tuesday's dramatic victory over Montreal, the Washington Capitals tonight slid downhill faster than Annemarie Moser-Proll.

Pat Riggin, Atlanta's 20-year-old goalie, needed to make only 14 saves, few requiring extra exertion, to post his second NHL shutout as the Flames won, 3-0.

It was the fourth zero to occupy the Capitals' half of the scoreboard this season and the first time they have been blanked in 32 games, since Dec. 2 in Buffalo.

A further embarrassment was avoided with 2:19 left in the game when Antero Lehtonen recorded the Capitals' first shot of the period. Washington, which managed only three in the second 20 minutes and three in the third, never has gone a full period without a shot on goal.

Washington General Manager Max McNab, disturbed by the Capitals' poor play here in a 4-2 loss three weeks ago, flew down today for a close look. He left feeling even more disturbed.

"I wondered why they were so flat here last time and you can't pick up the little things on TV, so I felt I should be here," McNab said. "I can't figure it out. I wonder where the glue went. On the last road trip everybody had intensity, but tonight the desire to win wasn't there."

"There definitely was an emotional letdown tonight," Coach Gary Green said. "We didn't have the same life and intensity we had Tuesday. But this is a dead lifeless place. At least playing poorly, it puts extra pressure if they're booing you when you're on you."

The only people the fans booed tonight were themselves. At least, the announcement of the crowd figure of 6,218 drew boos, probably because the folks who really care can see their heros headed elsewhere.

The Flames have lost only one of their last 10 games, share second place in the Patrick Division and are tied for seventh overall. Still, it is apparent that few care, and those who came tonight showed little enthusiasm.

Bill Clement, onetime Capitals captain, started the scoring at 9:11 of the first period. Pekka Rautakallio, the game's No. 1 star, carried the puck over the Washington blue line and passed to his right to Clement, who drilled the puck from 50 feet over the left shoulder of goalie Roolie Boutin, making his first start since Jan. 30.

"I don't think Rollie expected that, Green said. "We were three on three, but we backed up and gave them the blue line. The last few weeks we've been standing up well at the blue line, but that time we broke down.

The other Atlanta goals came on deflections. Ken Houston's skate redirected a drive by Phil Russel, and David Shand scored on a blast that hit the skate of Washington defenseman Pat Ribble and caromed between Boutin's legs.

Meanwhile, Riggin had largely boredom to overcome at the other end. In posting their lowest shot total of the season, the Capitals had only three that tested the young goalie. Bengt Gustafsson rifled two tough ones in the first period and Riggin came out to foil a drive by Glen Currie early in the second. At one point, Washington went 28 minutes without a shot.

Currie was given a breakaway opportunity early in the third period, but Atlanta's Brad Marsh dove from behind and swept the puck away with the most exciting move of the night.

Washington seemed headed for a two-on-one break in the second period, until a beaten Flame tripped Mark Lofthouse. In falling, Lofthouse brought down Currie, wiping out the entire play. It was typical of a night on which nothing went right for the recent heroes, from the early moments in which Rick Green took a run at Atlanta's Paul Reinhart, missed and went head first into the Atlanta bench.

"It was just a dead, lifeless night," Gary Green said.

"We have to get it out of our system and bounce back Saturday. I guarantee we'll win that one."

The way the Capitals ride the roller coaster of magnificence and malfeasance, the Chicago Black Hawks should consider themselves warned.