"You can't win without defense," the football sages say.

In the year I.B.S. (before strike), the New York Giants came within two touchdowns of the NFC championship game, despite a mediocre--and the adjective is generous in this case--offense. The Giants had DEFENSE.

The San Francisco 49ers, who ousted those same Giants by those same two touchdowns, and went on to win the Super Bowl, were acclaimed for the passing offense Coach Bill Walsh created and quarterback Joe Montana ran to a "T." Fact of the matter is, the 'Niners had played an almost identical offense to the tune of a 4-12 record only one season before. They came out of nowhere to win it all because of three things: a maniacal pass rusher they stole from San Diego, an Ironman middle linebacker they wangled out of the Rams; and three rookie defensive backs they plucked from the college ranks. The 49ers had DEFENSE.

And yes, those Steeler Super Bowl winners of the '70s did have Terry Bradshaw, Franco Harris and Lynn Swana gathering bunches of touchdowns during their Sunday walks down the football field. But the Steelers also had DEFENSE, as in Mean Joe Green, L.C. Greenwood, Ernie Holmes, Dwight White, Jack Lambert, Jack Ham, Andy Russell, Mel Blount, J.T. Thomas and on and on and on It was defense that filled Steeler fingers with Super Bowl rings.

The football sages aren't football sages for nothing, you know.

After Harvard's 34-0 rout of Brown Saturday at the Stadium--the first shutout for a Harvard team since a 10-0 sleepwalk over UMass in the second game of '78--the sages around these parts must be perking up a bit. 'Cause the Harvard football team has got DEFENSE. And it may just carry the Crimson to an Ivy title.

"That's just one heckuva football team," said dejected Brown Caoch John Anderson after Saturday's game "Especially on defense [Scott] Murrer at middle guard, and the two defensive ends. [Joel Margolis and [Pat] Fleming, are as good as any in this league. The same goes for the linebackers [Andy] Nolan and [Joe] Azelby--they're incredible. I don't think there's a team that I've seen this year that's comparable to them."

Anderson, it should be noted, has seen both Holy Cross (7-1 in Division 1-AA, including 3-0 against Ivy schools) and Penn, which Brown lost to, 24-21, three weeks ago, and which shares first place in the league with Harvard. The Crimson will find out exactly how it compares with each; next week the team travels to Worcester to meet The Cross, and in two weeks, it's off to Philadelphia for a chance to clinch a tie for the Ivy title.

Anderson was most willing to rave about the play of Murrer, a graduate of St. Xavier High in Cincinnati who signed a national letter of intent to accept a football scholarship at Notre Dame, then decided Harvard was the place he'd rather be.

"I'll tell you," Anderson said, "that Murrer is something. I haven't seen anybody play as well in our league. They talk about Kevin Czinger [the Yale middle guard who graduated in 1981] but this guy's just as fast, and a lot bigger and stronger." Czinger, who anchored the mighty Eli defense that stopped Harvard, 14-0, in the fall of '80, was named both Ivy and New England Player of the Year for his ferocious play that season.

"Being compared to Czinger is nice," said a flattered Murrer, who captains the Harvard track team when he's not plowing thorugh opposing centers. "It's an honor. I don't think I play the same kind of football he did, but it's just really nice to be compared to him."

Margolis also had an outstanding game against Brown, needing no Halloween costume to send shivers down the spines of Bruin QB Joe Potter. On one notable play in the first half, Potter dropped back to pass, and the protection looked adequate. All of a sudden, he glanced over his left shoulder and saw Margolis, all alone, coming with nostrils flaring. Potter panicked, as he did much of the afternoon, and just let the ball go. The pass hopped, skipped and jumped its way to an incompletion.

The Harvard Secondary, with an Ivy record-tying six interceptions for the second week in a row, also excelled. Said cornerback John Dailey, who had two of those interceptions; "We know we've got the best defense this school has had in a long time."

On that defense the Harvard football team rests.