Clarkson upset Harvard, 5-4, in overtime Friday night in Potsdam, N. Y., to avenge an earlier loss in the ECAC Holiday Tournament and hand the Crimson its first loss of the season.

Harvard managed to escape upstate New York with a 1-1 record for the weekend by edging St. Lawrence, 2-1, Saturday evening.

The two-game performance was disappointing for the Crimson, which had looked strong against a series of tough early-season opponent and then won the ECAC tournament. Harvard will have to regain some of its finesse if it is to beat both U. N. H. and Cornell later this week.

The Clarkson game was an even, roughly-played contest with neither team ever able to go ahead by more than one goal.

Dave Hynes put the Crimson on top, 1-0, in the first two minutes of action, and Clarkson didn't respond until Alf Machi tied the score late in the first period. But after that, a go-ahead tally by one team was followed quickly by a tying goal by the other.

The winning goal came at 0:58 of the overtime period when Steve Warr fired a slapshot past a hopelessly screened Bruce Durno just after Joe Cavanagh and Dan DeMichele had collided in their own zone. Durno had made 29 saves to 19 for Clarkson's Bruce Bullock.

Harvard's Bill Corkery, who came to life in the ECAC tournament, continued to score. He got his team's second goal against Clarkson with assists from Hynes and Bob McManama when both teams were even. Tommy Paul and Cooch Owen were Harvard's other scorers.

The roughest playing of the game came in the second period, when Harvard earned eight penalties and Clarkson four. On three occasions in the period a pair of opposing players went out for roughing.

Corkery scored the winning goal in Harvard's lackluster win over St Lawrence in Canton. It came at 2:10 of the final period, over 15 minutes after Cavanagh had tied the score at 1-1.

The Crimson got off 23 shots to St. Lawrence's 22.