When a dubious pass interference call was charged to an aggressive Cabot-North defender in yesterday's house football championship, one of the 70-odd fans screamed to the officials, "Let 'em play the game!"

And that's exactly what the Quadlings did all day long in their 13-0 shutout of Quincy House in the Stadium.

With its sixth victory of the season, Cabot-North ends the year undefeated and unscored upon. Meanwhile, Q-World--now 5-1--suffered its first loss. Both squads will travel to Yale Friday to play the top Eli house football teams.

As usual, a good running attack and an aggressive defense propelled Cabot-North. But this time the running star was fullback Tim McMahon, not fellow back Jerry Roper.

With his team playing in the Stadium for the first time this year, McMahon looked like Robert Santiago--the backfield talent who usually dominates home games--by carrying for 78 yards and two touchdowns on eight carries.

"It was fun playing on a real field with a lot of fans," McMahon said.

But based on its offensive performance, Q-World might have felt more at home elsewhere.

The first serious Quincy blunder occurred late in the first quarter, when a fourth-down snap sailed over punter John Toohey's head and ended up deep in Quincy territory.

McMahon capitalized on the error with an 11-yd. touchdown run on the first Cabot-North play. Following good blocks by linemen Tom Moffatt and John O'Brien, he ran through the hole and shook off several attempted tackles en route to the endzone.

Although Quincy's offense didn't move very far in the first half, its defense managed to contain a potent Cabot-North squad. The Quadlings, who scored 78 points in the previous five games, had to settle with just six at halftime, as Quincy held Roper to just 23 yards overall and forced him to cough up the ball twice.

Cabot-North's defense was equally sharp but much more intimidating and hard-hitting. Moffatt, Brad Doll and Rich Lafont constantly rushed Quincy quarterback Danny Sullivan out of the pocket and forced several errant passes, while Jon Pelletier and Jeff Hull delivered fear-inspiring tackles.

An interception by Quadling Paul Vallone and a personal foul penalty assessed against Quincy gave Cabot-North excellent field position, thus setting up McMahon's second score.

"Timmy read a beautiful block by Rich LaFont," Roper said of McMahon's 33-yd. touchdown scamper. "Timmy just couldn't be denied today."

Using Lafont's block and a block delivered by Zurasky, the Brookline native cut to the outside on a trap play and outraced the Q-House defenders.

With the win, Cabot-North replaces Quincy as reigning house football champions.