ITHACA, N.Y.--The weatherman predicted that Saturday would be a beautiful day for football. It wasn't Cornell expected to break down the Harvard defense. It didn't. The odd-smakers predicted the Big Red would subdue Harvard. It couldn't.

In an amazing display of superlative defense, get-it-when-you-need-it offense, and pure guts, the Harvard football team continued its Cinderella drive for an Ivy title Saturday, convincingly thumping Cornell, 21-15, here, to extend the Crimson's unbeaten record through four games.

Once again, it was the indomitable Crimson defense that led the way, setting up two of the Crimson's three touchdowns, sealing off the Cornell running attack, and forcing the Big Red so far out of its accustomed mode of attack that Cornell quarterback Mark Allen had to put the ball in the air 52 times in an effort to generate some offense.

Defense Strikes

The Harvard defense struck first midway in the first quarter. With the defense shutting down the Cornell attack to such a degree that the Big Red was allowed only 13 plays in the first three series (one over minimum), middle guard Sandy Tennant broke through on a fourth-and-one situation to block Cornell kicker Bernie Szynalski's punt and tackle Bob Shaw recovered for Harvard to give Harvard possession on the Cornell 26.

From there Crimson quarterback Jimmy Stoeckel wasted no time pushing Harvard into the end zone. After Ed Cronin bulled off right tackle for four tough yards, Stoeckel clicked with split end Pat McInally for nine yards and a first down at the Cornell 13.

Fullback Neal Miller hit for three more, setting up a Stoeckel-to-McInally completion in the middle of the end zone for the score. With Bruce Tetirick's conversion. Harvard had seven points and a lead it would not relinquish the rest of the afternoon.

The rest of the half settled down into a scoreless battle, with the Crimson defense repeatedly stifling the Cornell attack and the Harvard offense squandering chances to up the margin. Cornell did manage to break into the scoring column, via a 24-yard Szynalski field goal, but had little else to show for its effort.

The only real excitement generated by either team before halftime was a spectacular 67-yard kickoff return by sophomore Burrelle Duvauchelle after Szynalski's field goal.

Duvauchelle took the ball on his own four-yard line and followed perfect wedge blocking up the middle to break free. Duvauchelle cut to the outside after bursting through the Cornell coverage and eluded two tacklers before being dragged down at the Cornell 27.

Harvard kicked off to open the second half, and while the Crimson offense tried to counter the locker-room adjustments made by the Big Red at halftime, the defense thwarted Allen's aerial assault. Crimson captain and safety Dave St. Pierre, engaging in a brilliant battle with Cornell halfback Dan Malone during this period, repeatedly batted down Allen passes deep in the Harvard secondary.

Crimson opportunism struck again midway through the third period. Allen handed off to Malone, but a devastating gang tackle on the Red halfback disengaged the ball. Tennant, with a vacuum-cleaner-like efficiency, gathered in the football.

Stoeckel whipped Harvard 45 yards for the touchdown in eight plays, with a 29-yard completion to tight end Pete Curtin, the big gainer. Alky Tsitsos went off left tackle for the score.

Cornell fought back in the fourth quarter, controlling the Crimson attack and scoring on a three-yard pitchout to Dan Fanelli.

But Harvard bounced right back. The alert Crimson punt coverage unit jarred Cornell deep safety Scott Millhouse on the Crimson 20 to force a fumble and give Harvard the ball again. Two plays later, Stoeckel bootlegged around right end for what proved to be the game-saving touch-down.