Pete Peeters, warmly welcomed back to Boston by the Bruins' fans, left them muttering tonight with a 33-save effort that carried the Washington Capitals to a 2-1 victory.

Mike Gartner and Bob Carpenter, continuing to emerge from the doldrums, produced the shots that beat Boston goaltender Doug Keans, who was outstanding, too, with 32 saves.

Keans started instead of Pat Riggin, preventing a matchup of the Nov. 14 trade principals, because, Boston Coach Butch Goring said, "It is always very tough for a goaltender to play against his old teammates, and it works as an advantage for a hockey team to come out and play against its old goaltender."

Washington Coach Bryan Murray won the battle of wits with an opposing viewpoint: "I wanted Pete to be put in a pressure situation, to see how he responded. He's shown in games where's he's been slow to start and tough late, that he needs pressure to play under."

Peeters responded in grand fashion tonight, especially during a 15-shot Boston barrage in the first period.

"I tried to treat it as another hockey game," Peeters said. "I wanted to get my emotions under control and think about what I had to do. I just focused on the game and getting some shots early helped me get into it."

This was a classic up-and-down battle with playoff overtones, marred only by intrusive television commercials, and it took a big break to decide it.

With the score tied 7 1/2 minutes into the third period, Boston's Mike O'Connell fell while carrying the puck behind his own net. Greg Adams quickly took advantage, grabbing the puck and passing to Carpenter in front for the game-winner. It was the first goal here for Carpenter, a native of nearby Peabody, since he beat Rogie Vachon on his first visit 4 1/2 years ago.

Peeters made several good stops the rest of the way as Washington earned its 17th one-goal victory against three such defeats. Peeters foiled Barry Pederson after the puck hopped past Scott Stevens to give Pederson a breakaway. Then, with 2 1/2 minutes remaining, he made two good saves on Charlie Simmer.

The Capitals, who have lost only once to Adams Division teams in 12 games, were in such control over the last two minutes that Boston was unable to lift Keans for a sixth skater until only 10 seconds remained.

"We said before the game that we were playing a good team that's hot in their building," Murray said. "We didn't respond in a few games on the road against good teams and bad, but this time we came through with a lot of effort.

"We had a lot of chances, two-on-ones and three-on-twos, and when we didn't finish, I was afraid we'd make a mistake and lose it. Instead, they made the mistake."

The Bruins were playing their first home game since Feb. 9 and Goring said, "We didn't play that great, maybe because of the road-trip blues that seem to hit you when you first come home.

"No question, the winning goal was not a classic. But I think they (the Capitals) had the better of the play. We would have been fortunate to come away with a point."

The Bruins scored first. Ray Bourque beat Peeters from the left point early in the second period, with Simmer screening the goalie. Ken Linseman won a faceoff from Carpenter in the Boston end to set it up.

After Dave Christian hit a post, Gartner pulled Washington even with his 31st goal. Gartner dropped a pass for Bengt Gustafsson after crossing the Boston blueline, then broke past the defense, took Gustafsson's return pass and lifted a shot over Keans.

The crowd of 12,820 was highly displeased with the goal, contending with some validity that Washington captain Rod Langway should have been whistled for a hook at the other end before the play developed.

The Capitals came close a number of times the rest of the second period, but a couple of promising shots went wide, and Keans made big saves on Christian and Kevin Hatcher.

Besides Peeters and Carpenter, another Capital with Massachusetts roots played a big part in the outcome. Langway, who missed the last game because of a bruised thigh, was so dominant on defense that he was voted the No. 1 star.

Washington played without right wing Craig Laughlin, unable to skate because of a severely sprained left ankle, and defenseman Peter Andersson, who developed a sore left leg during the warmup.

Boston was missing defenseman Mike Milbury, who had played the last seven games because of shortages caused by a multitude of injuries. Milbury tonight refused to dress and returned to his role of assistant coach. Flames 7, Flyers 4

Philadelphia had a 49-29 shooting advantage in Calgary, but Rejean Lemelin's goaltending prevailed. The score was 6-1 after two periods. Rangers 8, Penguins 3

In New York, Mike Ridley got two goals, Barry Beck a goal and two assists and Reijo Ruotsalainen four assists against Pittsburgh. Blackhawks 6, Kings 3

Troy Murray used a last-minute empty net at Los Angeles to complete his first hat trick of the season and assisted on two goals by linemate Ed Olczyk. Murray and Denis Savard, who scored one, each has 41 goals to beat the Chicago record for a center set by Stan Mikita in 1967-68.