Bobby Gould was worth his weight tonight. For the rest of the Washington Capitals, the team's long-savored playoff debut is best forgotten.

Gould scored both Washington goals, but Bryan Trottier matched them and his teammates produced enough helping hands for the New York Islanders to record a 5-2 victory in the opener of their best-of-five Stanley Cup series.

When Gould scored the game's first goal, a sense of history raised hopes of a Capitals' upset. During the regular season, the Islanders lost the last five games in which the opposition scored first and won the last nine in which they posted the opening goal.

For the three-time defending champion Islanders, however, the playoffs are special, with regular-season statistics of little meaning. That proved to be the case tonight, as they outshot the Capitals by 30-13 over the first two periods and built a 4-1 lead with the aid of three power-play goals.

Washington refused to go away quietly and tested Islander goalie Bill Smith 16 times in the final period, but only Gould could slip the puck behind him. Still, the effort over the last 20 minutes was sufficient to inspire hopes of a turnabout when the series is resumed here Thursday night.

"We played with a lot of enthusiasm in the third period and we did a good job forechecking them," said Washington Coach Bryan Murray. "I don't know whether possibly they let up with the lead, but after having that type of third period, I think we can look forward to continuing it right from the start tomorrow."

The Capitals did not start all that badly tonight. While some of the playoff-tried veterans were struggling, the younger players gave the Islanders a battle. But it was obvious from the beginning that New York's strength would be a factor. The Islanders were finishing their checks and preventing the Capitals from starting plays, while New York was moving out of its end with relative ease.

Washington's first playoff goal was most unusual, in that it was the first power play score of the year for any of the three members of the Gee Whiz Line. Only eight seconds remained on a penalty to New York's Dave Langevin when an offside call brought a faceoff outside the Islanders' blueline. Murray gave up the pursuit of an extra-man score and sent out Gould, Glen Currie and Gaetan Duchesne.

Trottier won the faceoff from Currie, but he drew the puck back only a few feet and Gould pounced on it. He cut inside defenseman Mike McEwen and, when Smith went down prematurely, Gould lifted the puck over his left shoulder.

"I was just trying to step inside the defenseman; I wasn't trying to anticipate Trottier winning the faceoff, although maybe we should, he controls so many," Gould said. "It was a fortunate goal, just a result of circumstances."

The goal, which came two seconds before Langevin was due to return, ended a string of 19 power play failures for Washington against the Islanders.

The Capitals' next extra-man opportunity backfired in damaging fashion. Greg Gilbert's high-sticking sentence was negated 57 seconds later by a tripping call on Washington's Ken Houston. Then, just as the four-on-four segment ended, Brian Engblom lost the puck leading a rush into New York ice.

Gilbert jumped out of the box and the Islanders mounted a four-on-one rush, with only Duchesne able to get back. Goalie Pat Riggin made a fine stop on Denis Potvin's deflection of a long shot by Mike Bossy, but Potvin crashed into Riggin and there was no defense for Trottier's rebound.

Possibly the biggest play of the game occurred late in the first period. Timo Blomqvist's blueline-to-blueline pass freed Bengt Gustafsson on a clean breakaway but the Swede, after attempting to deke Smith, shot the puck directly into the goalie's pads.

"That was a real key play, no question," Murray said. "I think in quality chances it was a much closer game than the score indicates. We had a lot of good chances, but Smith, as usual, was tough."

New York's extra-man unit, fifth best in the NHL during the regular season, added two more goals during a second period in which the Islanders outshot Washington, 16-6, and built a 4-1 lead.

Blomqvist was off for holding when Anders Kallur put New York ahead to stay. Washington's Rod Langway came far out to challenge Stefan Persson near the blueline and could not get back when Persson fed Kallur on the left wing. Engblom dove too late to stop Kallur from lining a shot off the far post into the net.

It took the Islanders only 64 seconds to expand their margin to 3-1. Butch Goring made a remarkable backhand pass out of the right-wing corner between Langway's skates to John Tonelli cutting in front of the net. Tonelli lifted the puck over Riggin's glove for his 20th Stanley Cup goal.

It became 4-1 late in the period, after Gustafsson drew a penalty for tripping Trottier while Trottier was attempting to forecheck Engblom in the Washington end.

Riggin got a skate on a Trottier drive from the slot, but he was helpless when Gould deflected a Kallur pass and the puck wound up on Trottier's stick just outside the crease. Trottier beat Riggin on the short side while the goalie was frantically moving from right to left.

Gould gave the Capitals renewed hope with his second goal just 19 seconds into the third period. Skating down the left side, on his offwing, he cut around Bob Nystrom and fired a shot from a bad angle that handcuffed Smith. Nystrom tried to hover over the puck until Smith could freeze it, but Gould got there first and caromed a shot off Smith's leg into the net.

"Nystrom had a glove on it, but he let it go, because (referee Wally) Harris was right there and it would have been a penalty shot," Gould said. "It went off the back of Smitty's leg. It was a lucky goal."

Nystrom concluded the scoring by converting a cross-crease pass, then Smith took over and frustrated the Capitals, to the delight of the sellout crowd of 15,230, which paid from $19 to $29 for the privilege of chanting "Bill-ee, Bill-ee." It was Smith's 61st playoff victory, against 21 losses.

Gould said the Capitals need to play the entire game Thursday the way they skated in the third period to even the series.

"We can't go down, 2-0," Gould said. "We wanted to win one of the first two and we just have to do it tomorrow. I was a little tight early in the game tonight and I think everybody was. We laid back a little and didn't want to take chances. In the third period, we were a little loose and we got on them.

"When I first played in the playoffs at Calgary, I'd just been called up and I felt I had nothing to lose, so I just went out and played. Maybe that's what we have to do here and not worry about what happens."