For the first time this season, the Washington Capitals have lost three straight games. The timing hardly could be worse.

By losing, 3-2, to the Boston Bruins yesterday at Capital Centre, the Capitals dropped out of first place in the Patrick Division for the first time since Jan. 14. They trail Philadelphia by two points, and the Flyers have a game in hand.

Entering the third period with a 2-1 lead, the Capitals had every reason to expect to win this one. They had lost only once all season when they were ahead after two periods and Boston, struggling to extend a streak of 17 straight winning seasons, had rallied to win only once before.

A holding penalty to Bob Carpenter opened the way for the Bruins to tie it up, since each team already was a man short when he pulled down Geoff Courtnall in front of the Capitals' bench.

On the ensuing power play, Washington goalie Pat Riggin came well out of the net to block a long shot by Mike O'Connell. That is a good move in a five-on-five situation, but in this case it was disastrous. Although Rod Langway was able to deflect Ray Bourque's rebound, the puck caromed into the crease and Ken Linseman shoved it into the empty net with 12:37 remaining.

Dave Donnelly, a Canadian Olympian who played for North Dakota's 1982 NCAA champions, produced the winner, only his fifth goal of the season, with 2:25 left on the clock.

Keith Crowder's pass out of the right wing corner was deflected by Washington's Scott Stevens and popped onto the stick of Steve Kasper outside the right post. Although Riggin stopped Kasper's backhander, Donnelly slid the rebound under the right pad of the goalie, who had entered the contest with a 9-2 record against Boston.

"Steve put it up to the net and he (Riggin) came across and fell back," Donnelly said. "I got there as fast as I could and jammed it in. I'm just glad I could help the team."

The Capitals also received help from an unexpected source.

Defenseman Dave Shand, making his ninth appearance of the season and first since Feb. 23, netted his first goal to open the scoring and delivered smashing checks on Dave Reid and Linseman before engaging Courtnall in a fight. Shand was injected in place of Mike McEwen to provide, according to Coach Bryan Murray, "something we don't have -- life, spirit on the ice and spirit on the bench."

"I'm not going to score goals, but I can be enthusiastic and get involved and hit," Shand said. "That's the only way I can play."

Some observers wondered why Shand had not played more after doing well last season, but he said, "They made decisions in training camp to go with guys who have a lot more talent than I have. With the team going so well, there was no reason to change.

"But when you're in a down streak, that's when you experiment and make changes. Unfortunately, now we're in that kind of streak."

One of the major reasons why the Capitals did not snap out of their downward spiral was Boston goaltender Doug Keans, who made 27 saves and turned in his best stops when it seemed the Capitals might break the game open.

With Washington ahead, 1-0, and applying power play pressure, Keans made a skate save on Stevens and blocked Gary Sampson's point-blank rebound. Later, with Washington in front, 2-1, Keans stopped Mike Gartner's deflection of a drive by Larry Murphy.

"We had enough chances to win," Murray said. "In the last minute, with our goaltender out, we had two or three great chances in the slot. Maybe it was Keans or maybe it was us. We weren't patient enough, or maybe we weren't good enough."

Keans, who shut out Hartford in his most recent start, was more charitable, suggesting that luck had a lot to do with it.

"Sometimes no matter what they do, we stop it, and other times all the shots go in," Keans said. "A lot of it was just luck today. They'd throw the puck at the net and crash the net and I was getting knocked over a lot. I was just trying to make the save and rely on my defense and forwards to clear the rebounds. That was the difference today -- the way we cleared the rebounds."

Carpenter lost his edge going for a rebound of a second-period shot by Shand and crashed into Keans, necessitating a brief delay while Keans sniffed smelling salts. "My head was against the post and when he hit me, it jammed my head against it," Keans said. "It kind of stunned me for a minute."

Thereafter, Keans was a standout. The only goal he allowed after he cleared his head came on Dave Christian's brilliant setup of Gaetan Duchesne late in the second period.

Boston had pulled even midway through the period on Bourque's 15th goal, a power play score on which his drive from the left point struck Duchesne's glove well outside and changed direction sufficiently to fool Riggin.

But Christian brought the sellout crowd of 18,130 to its feet with a marvelous move down the left side. He faked defender Brian Curran to the ice, skated around him and was a foot from Keans' stick when he made a backhand pass to Duchesne.

"Davy made a great, great play," Duchesne said. "He faked out everybody and put it right on my stick. Bourque was right with me, but I just put my stick on the ice and it was in the net."

So the Capitals were on a high when they went to the dressing room after the second intermission. The next time they trudged in, they were at their lowest point of the season.

"We should never have lost to the Boston Bruins," Duchesne said. "When you've got a 2-2 game in the third period, a good defensive team never gives up a goal like that at the end.

"It was a tough goal for us. We'll take a tie if we can, but now we get no points and it puts a lot of pressure on us."