TROY, N.Y., Jan.2--They call hockey Canada's national sport and the Canadians certainly showed why this week. A smooth-skating Saint Francis Xavier sextet from the wilds of Antigonish, Nova Scotia, blasted three of the East's top-rated hockey teams to win Rensselaer Polytechnic Institute's third annual invitation tournament.

Princeton, last year's Pentagonal champions, Brown, favored to win this year's Ivy title, and host R.P.I., last year's unofficial Eastern champions, fell successively before the Canadian onslaught. St. Francis topped R.P.I., with six Canadians of its own, by a 4 to 1 count in the tourney final.

All in all, it was a bad week for the Pentagonal representatives. On the first night of the tournament, St. Francis coasted to a 5 to 3 win over Princeton as the Tigers escaped a shutout only by a scoring flurry in the last ten minutes. In the other opener, R.P.I. manhandled Brown 5 to 1. Then R.P.I. and St. Francis switched Ivy opponents and proceeded to the tournament finals with easy victories. St. Francis broke loose in the third period for five goals and an easy 8 to 1 win over Brown, while R.P.I. shut out Princeton 5 to 0.

For a while it looked as though the two Pentagonal teams couldn't even beat each other. In the play-off for consolation honors, Brown and Princeton battled evenly and impotently for 59 minutes and 39 seconds. Then, with the score tied at 1-1 and only 21 seconds left, Brown's standout center, Danny Keefe, slammed the puck past the crestfallen Blair Torrey, Princeton's star goalie, to give the Bruins an unexpected win.

No Terrors for Crimson

Off their tournament performances at least, Princeton and Brown should hold no undue terrors for the Crimson in the coming Pentagonal campaign which gets underway Saturday night. The Tigers have a fine goalie in Torrey and a rugged defenseman in Dick Court, who made the all-tournament first team, but they lack a dependable scoring punch. Brown is an aggressive squad, paced by the hot-tempered Keefe and bad-man Dick Pettit, but the Bruins looked far out of their class against both St. Francis and runner-up R.P.I.

St. Francis unquestionably gave the tournament its real color; the Jesuit school from the far north featured players with such picturesque names as Fraser O'Shaughnessy and Alex MacSween in its starting line-up. And St. Francis even sported a priest, Father Andy Hogan, in the coaching spot. As one spectator groaned after watching the Canadians in action; "These guys even have God on their side."