For the first time in their nine-year history, the Washington Capitals have compiled a 10-game unbeaten streak. Defeating the Los Angeles Kings, 7-2, last night at Capital Centre, they matched the longest undefeated string in the National Hockey League this season and took over third place in the Patrick Division, two points ahead of the New York Rangers.

Even more significant, to long-suffering fans of a never-in-the-playoffs team that 11 times has had winless streaks of 10 to 25 games, the capitals are two points out of second place and five points from first.

The last home game before Christmas produced the Capitals' highest score of the season. Seven players scored, to spoil the celebration for the Kings' Marcel Dionne, who got both his team's goals and became only the ninth player in NHL history to top 500.

Dionne did not get a hat trick because after his 501st, which tied the score at 6:31 of the second period, he was checked by Glen Currie and his comrades on the "Gee Whiz Line."

Bobby Gould and Gaetan Duchesne, both on Currie setups, gave the line its first multigoal game since the night Currie was recalled from Hershey, Nov. 7. Incredibly, playing a regular shift, the line has not allowed an opposition goal during the 10-game stretch of success.

"I just told Mr. Pollin that if Currie ever learns to score, he won't be able to afford him," said Coach Bryan Murray. "He does everything else so well. His line was on top of the Kings almost every shift they were out there."

Gould's eighth goal resulted from a steal by Currie in front of the Los Angeles net, as Currie picked Jerry Korab's pocket, was stopped by goalie Gary Laskoski and watched Gould net the rebound. Duchesne's sixth was an easy lift over Laskoski from just outside the crease after some outstanding forechecking by Currie and Gould.

Dennis Maruk's third goal in two games created a 1-1 tie midway through the first period. He blocked Rick Chartraw's attempt at a clearing pass, then got the puck back from Doug Jarvis and beat Laskoski from deep in the left-wing circle.

In the second period, Murray temporarily shifted Maruk to center and he was a key factor in goals by Mike Gartner and Paul MacKinnon that helped the Capitals turn the game into a rout. Then it was back to stating up and down the left wing.

"I decided we needed a goal or two to get things going," Murray said. "Dennis is dying to get back at center and I kind of tease him to get him going out there."

MacKinnon's goal was his first this season and his fourth in the NHL, enabling him to catch teammate Randy Holt, another notable nonscorer. To illustrate how well all the Capitals performed in this game, however, Holt made perhaps the best pass of the night to set up Bengt Gustafsson for the goal that ended a 2-2 tie 25 seconds after Dionne created it.

Holt skated down the right wing and was confronted by defenseman Larry Murphy. Holt slipped the puck around Murphy to Gustafsson, who was skating down the slot and easily beat Laskoski.

Both Holt and MacKinnon performed admirably in longer shifts than usual.

"This is the first game that wasn't close," MacKinnon said. "It's tough to play with confidence when you only go out a couple of times in a close game. Tonight I felt comfortable out there."

Milan Novy, who got his sixth goal in the last five games against Laskoski's successor, Mario Lessard, was whacked on the right elbow and will be X-rayed today to determine whether it is more than a bruse.

"It happened in the first period," Novy said through an interpreter. "A defenseman behind the goal struck me with his stick."

"We skated as well as the team has skated all year," said Bryan Murray. "We were all over them offensively and I think we just wore them down. We moved the puck extremely well all night."

While the Capitals maintained their roll, the Kings were extending their winless streak to five games. In the process, they lost defenseman Jay Wells, who had ligaments in his right knee damaged in a first-period collision with Alan Haworth.