Only one team in the National Hockey League has won seven games in 1979. Surprise: that club is the Washington Capitals, who delighted a Capital Centre turnout of 13,453 last night by thrashing the New York Rangers, 5-1.

For the first time in history, the Capitals were winning a fourth straight home game, and the fans responded accordingly.

"Those fans -- they sent chills up everybody's back when they stood up and cheered us," said Blair Stewart, whose remarkable pass to Ryan Walter set that rookie up for the game's first score.

Robert Picard, who netted the winner in the last minute of the first period, enjoyed his third two-goal game of the season and raised his point total to 39, a club record for a defenseman.

Picard saw considerable ice time in the closing minutes as Coach Danny Belisle sent him in search of a hat trick, but Picard said, "All I need is two points in the standings. I don't need the rest."

A splendid Washington defensive effort limited the Rangers to seven shots in the last two periods, giving goalie Gary Inness a rare chance to relax. Inness was superb, as usual, while the Rangers applied first-period pressure, yielding only a rebound goal by Ron Duguay.

If there is one memory the fans will carry from this game and cherish through future seasons, however, it was the second-period power-play goal by Greg Polis that boosted Washington's lead to 3-1.

Polis, a Ranger bench warmer most of the season, came to Washington nine days ago for $100. He is far from top shape and weight work has tightened the thigh muscles on both legs, so that he must apply heat to them before games and ice bags afterward.

Polis picked up the puck in the Washington end, skated down the middle, split Ranger defensemen Carol Vadnais and Dave Maloney, put a bodacious deke on goalie John Davidson and backhanded the puck past him. Polis then crashed into the boards, after banging his right shoulder on the goal post, but he was able to savor the crowd's admiration as he lay on the ice a few moments, then resumed play.

"It's always nice to score against a team you played with at one time," said Polis, who collected his first two goals as a Capital against another exemployer, Pittsburgh. "The guys in the dressing room before the game sit around and tell you to show them they made a mistake. It's a good feeling to do it.

"The play started in our end and as I picked it up I was circling, so I was in full flight. As I cut through center, I saw (teammate Dennis) Maruk at my left and Vadnais was in my way. I was figuring maybe pass, but then Vad pulled over and left me an opening in the center, so I gave it my shot.

"Davidson came out and I pulled it back and put it on my backhand and it went in. Actually, I just did it. You really don't think about it while you're doing it."

Polis and his teammates have been thinking about something else, the Stanley Cup playoffs, and five victories in the last six games have created an atmosphere of optimism unknown during Washington's four previous seasons.

"Winning is the only way to play," Polis said. "If it becomes a habit, it just continues. You just keep her going and when you play like that. the games fly by. All you're pointing toward is the next game and the next win.

"You look to the playoffs instead of just waiting for the season to end. It makes practice easier,, it makes living at home easier and it makes living with each other easier."

Walter's 40-foot blast, off that fine pass by Stewart, was his 19th goal and his eighth in the last seven games.

After Duguay equalized, New York's Dave Farrish went off for tripping Stewart. Guy Charron then skated around the blue line, searching for an opening, before feeding Rick Green at the left point. Davidson blocked Green's shot, but Picard moved in close, stopped the puck with his skate and fired it in.

"I saw Guy in the middle, in my position, so I figured if Greenie got the shot off I'd be there." Picard said of his move from his right point post. "It worked out perfect."

Charon's assist was his second of the game, giving him 200 points in 2 1/2 seasons as a Capital and providing a welcome 30th birthday present. He has collected 456 points in his career, but last night was the first time he was serenaded with "Happy Birthday" at a hockey game.

Anders Hedberg, the Rangers' Swedish millionaire, did not manage a shot on goal, although he was just wide on a first-period setup by Ulf Nilsson.

Phil Esposito didn't test Inness, either, and afterward the man Capital Centre fans love to hate gave full credit to the opposition.

"You guys got a lot of good young players here," Esposito said. "It's a good young hockey team. They work hard and they deserve a lot of fan support."

Belisle said he did not plan anything special to spike the big guns of the high-scoring Rangers.

"If I started going through their team, with Hedberg and Nilsson and (Don) Murdoch and Esposito, I'd be there talking half an hour," Belisle said. "I just worry about our team and playing our game. Let them worry about us.

"Right now I feel there's just no stopping us. We're going to keep it going. Everybody thinks team. They don't care who gets the credit as long as we win."

The officials had almost as much trouble as the Rangers. Referee Bruce Hood was delayed in transit, forcing linesman Matt Pavelich to call the first period. Then linesman Gordie Broseker was jammed against the boards and needed assistance.