Of all the sorry statistics connected with the Washington Capitals since their birth in 1974, none has been so wretched as the performance of the power play.

"Decline the penalty" was a witty fan's advice during a first-year contest in which Buffalo collected three short handed goals, two during one so-called advantage. That season, the Capitals yielded 18 shorthanded scores, an NHL record.

During the Tom McVie years, as the team grow more respectable in most areas, power play production actually declined, from 14.1 percent in 1975-76 to 13.3 percent in 1976-77 to 12.2 percent in 1977-78.

Things were so bad that McVie had his penalty killers practice holding their sticks by the blades, to give the power-play men more confidence. It backfired, as the stick knobs were sufficient to break up the play.

Last year, Danny Belisle gave the power play high priority and the percet percentage went up to 18.9, somewhat more respectable but hardly anything to brag about.

When this season started with 11 unseccessful power plays, there was reason to wonder whether the Capitals were forever doomed to extraman deficiency. And then, suddenly, it all came together. Washington has converted four of its last five advantages, and in no case was as much as a minute required to activate the red light.

During Tuesday's 8-6 victory over Los Angeles, the Capital's power play batted 1.000, with three quick scores by Ryan Walter, Robert Picard and Tom Rowe.

Although pleased with that aspect of his team's play, Belisle declined either to accept credit or to claim that things were really straightened out.

"The power play goes like that," Belisle said. "You go games without scoring and then it clicks. We've worked on it a little bit and we've had a few chalk talks, but we still have a lot of work to do on it.

"We have pretty good offensive punch this year. Last year we had six guys only, but now I can almost play any line and leave it intact. If one guy is having an exceptional game, maybe I'll move him onto the power play a little extra."

Walter was the man who saw the extra time during the weekend successes, helping the combination of Guy Charron-Mike Gartner and Dennis Maruk-Rowe make it work. The point men were Picard and Bengt Gustafsson, and the young Swede acquitted himself admirably. There is always a risk playing a forward at the point, but Gustasson recovers so quickly that he is able to ward off most opposition breaks.

"That is still at the experimental stage," Belisle said. "He's got good imagination, he has great speed to recover and he handles the puck so well. Even if he does fumble, he can come back. I'd say so far, so good on that move.

The power play should get a workout tonight when the Toronto Maple Leafs drop by Capital Centre for an 8 o'clock contest. The Leafs are always among the league's penalty leaders and last season ranked second to Philadelphia, with Tiger Williams the individual leader and Dave Hutchison No. 4.

To enhance the Leaf's brawling image, the Capitals have designated tonight as 25-cent beers night.

One man who will miss it is feisty winger Gary Rissling. The Capitals had Rissling sit around for two weeks while they sorted out some personnel problems, but yesterday Rissling was finally assigned to the Hershey farm club.

Maruk was named Player of the Week by Hockey News after a six-goal opening week. Maruk scored a goal each in the Captials' first two games, both losses, then capped the week with four goals as Washington beat with New York Rangers, 5-3, Sunday.