A freak goal late in the second period, a Michael Watson insurance tally at 9:16 of the third, and 35 saves from goaltender Wade Lau propelled the Harvard hockey team to a 2-0 victory over Boston College last night at Bright Center in the opening round of the ECAC playoffs.

The win sends the eighth-needed Crimson into a Friday night semi-final at the Boston Garden with top-ranked Clarkson. The Golden Knights advanced last night by defeating Colgate, 7-4, in Potsdam, N. Y. Number-two Northeastern, which came from behind to topple St. Lawrence, 4-3, at Northeastern Arena, and third-seeded New Hampshire, which held off Providence, 4-2, in Durham, N.H., will meet in the other semi-final game. The ECAC finals and consolation games will be Saturday, also at the Garden.

In nailing down their first win in an ECAC playoff game since stopping UNH in the first round back in 1976, the icemen relied on a little luck, some expert penalty killing and forechecking, and the super goaltending of Lau, who turned in his third shutout in his last four games. The game was very much like last year's Harvard win over B.C. in the Beanpot final, also by a 2-0 score, the last time Lau and Eagle netminder Bob O'Connor squared off.

"Oh yeah, it was a lot like that Beanpot game last year," a radiant Bill Cleary said afterward. "Both teams played really well. And the goaltending was super. I thought it was a great game."

For B.C. Coach Lon Ceglarski, whose current team is 0-7 in Beanpot finals and ECAC playoff games, it was one more heartbreaker.

"I just don't know what to say," a very quiet Ceglarski said outside a very quiet locker room. "These kids have just worked their hearts out for three years. Whatever has come to them, they don't deserve. I just feel sorry for the seniors--O'Dwyer. Sampson, all of them...We've got 10 seniors on this team.

"I don't want to take anything away from Harvard. They played well But I don't think they outskated us or outworked us."

Cleary agreed in dismissing the choke rap on the current Eagle squad, saying. "I hear that stuff all the time. But how can you fault the B.C. team? They played a helluva hockey game tonight."

Indeed, except for a six-minute stretch through the middle of the opening period--which included a Greg Olson wrist shot at the 10:30 mark that changed off the inside of the left post--the Eagles controlled much of the first 20 minutes.

Harvard's superb shorthand play, especially during three minutes and 49 seconds of B. C. power-play, (11 seconds were 5-on-3) from 13:17 to 18:06, kept the game scoreless until the buzzer sounded to end the first period.

Because of their intense pressure on the Eagle point men, the icemen continually stole the puck in their own zone and cleared. During the nearly four-minute man-down situation, the Crimson sent the puck the length of the ice four times.

Although each goaltender finished the opening stanza with 11 saves, it was O'Connor who put on the show, incurring a roughing penalty for hitting Scott Fusco in the head at 3:44 and denying both Fusco and Greg Olson from in close on several occasions.

The highlights of period two included some more outstanding play from O'Connor, who had 17 saves in 20 minutes, and the most bizarre goal that anyone has ever seen, a goal that turned out to be the game-winner for Harvard.

Jim Turner, who scored it, was as baffled as everyone else. "I saw Greg [Olson] and Scotty [Fusco] come back cut of the zone and figured I'd drop the puck back in. I shot it towards the boards and turned my back so I was facing Wade. The next thing I knew the puck was in the net."

What happened was that Turner's shot off the left side boards deflected off the shin guard of one of the referees, shooting into the zone toward the B.C. net. O'Connor, anticipating that the puck was headed for the back boards, got caught going the wrong way, and the puck just slid by him and inside the far post at 18:18.

In the third period, Captain Watson flipped home a rebound of a Tony Visone shot, at the 9:16 mark, and it was on to the Boston Garden and the Golden Knights.

"I'm not even thinking about them now," Cleary said. "We'll see 'em Friday night." THE NOTEBOOK: The stars of the game, as selected by the Cambridge media: Lau, Greg Olson, and Mitch Olson