The New York Islanders have not lost a game on home ice all season, so the Washington Capitals did not figure to extend their two-game winning streak tonight. They didn't.

The Islanders scored two goals in the first 132 seconds, started thinking about Wednesday's game with the New York Rangers by the time the score reached 4-0 and coasted to 6-2 triumph.

Denis Potvin posted his third career hat trick, ran his season goal total to 20 and emphasized once more his almost unchallenged right to the title of oustanding defenseman in the National Hockey League.

"If we had him (Potvin) and (Bryan) Trottier, we'd be in second place behind Montreal," said Washington Coach Danny Belisle. "They're head and shoulders above everyone else. We're in a little deep with teams like Montreal and the Islanders. Everything has to go right for us to best them and they have to have tough luck. But they don't seem to have any."

The Islanders have recorded 18 victories and four ties in 22 home games, have lost only two of their last 33 games and just five overall, and now boast 16 victories and three ties in 19 lifetime meetings with Washington.

Mike Bossy collected his 36th goal for New York, while Trottier, the league's leading scorer, earned three assists to run his point total to 76.

The Islanders applied intense pressure from the start, forcing Washington goalie Gary Inness to make some difficult saves and driving another shot off the post before Clark Gilles connected with a bouncer from the slot at 1:36.

When Washington's Gord Lane was penalized for crosschecking Bossy, the Islanders sent out the NHL's most sucessful power play and it took only 12 seconds for Potvin to blast a 45-footer past Inness.

Bossy converted a two-on-one with Trottier at the 10-minute mark to make it 3-0, after defenseman Bert Marshall had checked Ron LaLonde off the puck at the other end.

Potvin, once again skating in unmolested from the left point, made it 4-0 with another power-play score at 2:32 of the second period. Ryan Walter was was off for holding at the time. The two power play goals gave New York 45 in 137 chances for 32.8 percent success, The Capitals' penalty killing fell to 70.5 percent, just one tick away from Colorado in the futility race.

Walter backhanded his 17th goal from the slot to ruin goalie Billy Smith's shutout bid late in the second period and Rick Green netted his seventh on a power play early in the third. Walter was becoming the sixth player in the Capitals' brief history to score goals in four straight games.None has ever reached five.

The Islanders, who fired only four shots at Inness in the second period, were revived by the Capitals' comeback and Potvinhs third goal, plus Bob Oburne's 18th of the season, rebuilt the four-goal margin.

Walter needed five stitches at the corner of his left eye after being whacked by Potvin's stick in the first period.

"I think it was accidental," Walter said. "That's old-time hockey. The puck is coming to me in the slot, thanks to Guy (Charron) and Stewie (Blair Stewart) working the corners. If I ever get the puck to follow me around like that Bossy -- he's really something. And Trottier, Potvin, right down the line."

Left wing Greg Polis made his debut as a Capital, playing on a line with Rolf Edberg and Bob Sirois, and fired five shots on goal.

"I had some good chances," Polis said. "In another two or three games they ought to be going in. My game is a little not-quite sharp, because I haven't played in a month. In the past, some of those chances would have been in the net.

"I've got 101 million things going through my mind. I have two kids and my wife is seven months pregnant, but she's taking care of things so I can try to concentrate on playing."

"Polis has imagination and he has a plan in mind with the puck." Belisle said. "He looks strong in the corners. When he's in shape, he'll help our hockey club."

Michel Bergeron, cross-checked by Marshall, repsonded with a nifty left hook that drew blood from the Islander's mounth.

Bergeron, acquired from the Islanders in October, has his friends here, as evidenced by "We Love Bergy" and "Let's Go Bergy" banners dangling from the balcony. Marshall, however, is not one of his pals.

"We didn't get along," Bergeron said. "He didn't like me, so what could I do? I didn't like him, either. I didn't fight for a year and a half, but he went after me and wanted to go. I wasn't doing anything sitting on one bench, so I figured I might as well be on the other bench. I just hit him twice. I wanted to hit him in the nose, but I missed. Next time..."

Smith was forced to stop 29 shots as the Capitals had a 31-26 edge in that department. In 11 starts against Washington, Smith has posted nine victories and two ties, which gives him a onesied edge in summer bragging rights over his brother Washington defenseman Gord Smith.