By now, the Washington Capitals should be immune to last-minute disaster. Even longtime wearers of the red, white and blue were still shaking their heads last night, however, long after Mike Bossy's goal with 35 seconds left had given the New York Islanders a 3-2 victory at Capital Centre.

"It's so frustrating," said defenseman Rick Green, oldest Capital in point of service with six seasons here. "It's happened so many times. It's just maddening. The guys work really hard, yet every time we slip up at the end of a game, they capitalize. It's just got to change."

"It's discouraging when it happens at the last," said captain Ryan Walter, who scored one goal and set up the other. "When we're playing that well, we don't deserve to lose. A tie would at least have been a moral victory. We just have to keep plugging and turn it around."

"We're close to being a really good hockey team," said Mike Gartner, held without a shot on goal for only the second time in 98 games. "It's been this way for three years and we seem to get closer every year. We have to start winning these games. It's getting really discouraging, but we can't quit now."

Bossy's goal came on the only shot by either team during the last three minutes. Bryan Trottier cut in from the right wing and his backhander caromed off Green's leg and went behind the net. Trottier had kept on skating and was in position to pick it up quickly and feed Bossy, who hit from the left-wing circle.

It was Bossy's 58th goal and 137th point and it gave him an NHL one-season scoring record for a right wing, topping Guy Lafleur's 136 of 1976-77. The goal, the 299th of Bossy's career, came in his first appearance here since he earned MVP honors with two goals in the Feb. 9 All-Star Game.

For the fourth straight game, the Capitals carried a lead into the final period and failed to win, with this disaster following a frustrating 4-3 loss to the New York Rangers Saturday night.

The Islanders were playing without defenseman Denis Potvin and Washington tried to take advantage by repeatedly dumping the puck into the Islanders' zone. In the first period, the Capitals were able to take a 2-0 lead while limiting the visitors to four shots.

Both goals came on power plays, Chris Valentine netting his 24th from the slot on Walter's setup and Walter scoring his 36th by deflecting Green's drive from the left point.

Brent Sutter's successful screen enabled the Islanders to halve the deficit early in the second period, as Tomas Jonsson's 40-footer from the top of the left-wing circle sailed past goalie Dave Parro.

At the two-minute mark of the third period, Walter spun in front and fired a testing shot at goalie Bill Smith, who made an exceptional save. Shortly thereafter, Capital Lee Norwood was chased for cross-checking Anders Kallur and the Islanders' 28 percent power play, best in the NHL, created a 2-2 tie.

Bob Bourne put it in, on a close-range backhander from Parro's right after taking Mike McEwen's adroit pass from the left point that caught defenseman Terry Murray in the middle.

The Islanders' depth began to wear down the home side in the third period, when New York enjoyed a 14-6 edge in shots. But Parro made superb stops on Kallur, Dave Langevin and Stefan Persson, stimulating hope that the Capitals at least could escape with a tie.

There was a desperate moment when a rebound struck Islander Clark Gillies as he skated down the slot, but the puck struck a post and caromed wide. It seemed the Capitals' luck might be changing, but the 10,113 fans should have known better.