For No. 14, the Washington Capitals put a special ornament on the tree. With Mike Gartner scoring two goals and Al Jensen stopping 23 shots, the Capitals routed the Stanley Cup champion New York Islanders, 5-1, tonight and reached the Christmas break with a 14-game unbeaten streak.

It was the Capitals' first victory in 20 visits to Nassau Coliseum and they showed their hunger for it by racing into a 2-0 lead after just 3 minutes 1 second. Although a fluke goal got them within one, the Islanders never really recovered.

"We jumped on them and we were ready to play," said Bryan Murray, unable to hide his enjoyment of his 100th game as the Capitals' coach. "We took it to them pretty good most of the game. We're moving the puck so well from our end."

By winning a third straight road game in which they limited an opponent to one goal, the Capitals climbed into a second-place tie with Philadelphia in the Patrick Division, two points behind the Islanders. The Capitals have played five fewer games than New York.

In the first 85 seconds, the Capitals sent four shots at goalie Bill Smith, who was losing to Washington for only the second time in 19 decisions. Then Islander Dave Langevin hooked Dennis Maruk and it took the Capitals' power play just 15 seconds to put them ahead to stay.

Maruk scored it, his 18th of the season, sweeping the puck past Smith after Greg Theberge's drive from the point had caromed off defenseman Ken Morrow.

It became 2-0 at 3:01, after Washington defenseman Rod Langway had slid across the ice to block a shot by Tomas Jonsson. Milan Novy sent a headman pass to Gartner, who raced in on a breakaway and sent the puck over Smith's shoulder.

After a drive by Stefan Persson deflected off Mike Bossy's skate into the net, for Bossy's 27th goal, Jensen kept the Islanders from scoring. He stopped 18 shots over the last two periods, skating out as far as the faceoff hashmarks with complete confidence.

The Capitals increased their lead to 3-1 on a second-period goal by Bobby Gould. Maruk stripped the puck from Bossy inside the New York blueline and slid a pass to Gould, who got his 11th goal.

Jensen came far out to stop a drive by Bossy off the opening faceoff of the third period and handled a tough shot by Denis Potvin moments later. Then Langway checked Potvin off the puck at the Washington blueline and Bengt Gustafsson poked it ahead to Craig Laughlin, who turned it into a 4-1 lead.

"Al deserves a lot of credit for that save on Bossy," Langway said. "He may not have had a lot of shots, but he made three or four game-winning saves."

"Our line has been contributing by checking, but we like to chip in and score, too," said Laughlin, who was playing right wing with Ted Bulley on the left side of Gustafsson because Alan Haworth was out with a virus. "Three-one to 4-1 made a big difference."

Gartner completed the scoring with 7:08 left, scoring off a faceoff as Novy outdrew Wayne Merrick. It was Gartner's 22nd goal of the season.

At that point, thousands of fans rose and left. One person among the sellout crowd of 15,230 stayed to throw a bottle of beer that shattered on the ice. In another low point, Islander Bob Nystrom kicked Scott Stevens in the groin when they were separated after a last-minute fight. Nystrom received a match penalty.

"I guess they're just not used to losing," Murray said.

"We had no life; we played like a last-place team," said Islander Coach Al Arbour, who did not bother to speak to his players.

The Capitals not only were ending their own frustration here, which amounted to 18 defeats and one tie. They also were striking a blow for New Jersey, Quebec, Hartford, Winnipeg and Edmonton. Washington became the first team to enter the NHL after the Islanders (1972) to win at Nassau Coliseum, where New York had compiled a 52-0-10 record against the six newer franchises.

Jensen was building his own club record of consecutive unbeaten games to nine. He is 9-1-4.

"The team's streak is all that's important," Jensen said.

Novy needed stitches on his forehead after being rammed into the boards in the last minute, Maruk was cut on the left eyelid and in the mouth, and Stevens aggravated a bruised right hand injured in a fight last weekend. Nobody was complaining.

Other Games: The Nordiques beat the Canadiens for the first time this year, 6-1, in Quebec City. Michel Goulet scored one goal and set up two others, including Marian Stastny's game winner on a power play in the second period . . .

In St. Louis, Blake Dunlop and Blair Chapman scored power-play goals in the first period as the Blues defeated Toronto, 7-3 . . .

Mike Krushelynski's goal and two assists helped the Bruins beat the Whalers, 5-1, in Hartford, Conn. . .

Mike Blaisdell and Reggie Leach scored goals 10 seconds apart late in the second period as Detroit withstood a third-period rally and won, 6-4, in Detroit . . .

Edmonton scored four goals in the second period, with Wayne Gretzky getting his 28th, as it defeated host Los Angeles, 6-2 . . .

In Vancouver, Paul Reinhart's power-play goal at 12:01 of the second period broke a 3-3 tie and Mel Bridgman scored two later goals in Calgary's 6-3 victory.