The best thing about Notre Dame's 73-70 victory over Maryland yesterday at roaring, sold-out Cole Field House is that the Terrapins still haven't figured out exactly what happened to them.

What were those mysterious, hidden defenses that the Irish used in the second half as they went from five points behind to eight points ahead, then held on to win? Don't ask Maryland. By the time the Terps view the films and dope it out, Notre Dame will be out of town.

"They fooled us," said despondent junior point guard Dutch Morley, who played only six minutes and had a painfully good seat to watch his team's demise. "I've never seen us have so much trouble identifying defenses as we did in the second half.

"Too often, when they were in a zone, we'd be running our man-to-man offense. And when they were in a man-to-man, we'd be running a zone offense."

How can such an apparently simple breakdown occur at such a presumably sophisticated level of the game?

Easily, if Notre Dame's Digger Phelps is the man at the blackboard with the chalk in his hand.

"We play on national TV so much that we have to do some strange things defensively to keep people guessing," he said after his 12-3 Irish had beaten Maryland for the second straight year. "I'm not sure I want to discuss it all until April.

"I will say that we play a point (1-2-2) zone that we disguise. Most teams send through a cutter to identify what defense you're in. Some teams even send through a second cutter, just to make sure. Well, we play man-to-man until two players have cut through the lane. Then, we switch to zone. Not many teams are patient enough to keep checking what you're in."

That answers half the mystery. The other half, which Phelps isn't crowing about yet, is that he's found a way to change on the fly from zone to man-to-man, a tougher trick.

"After our first entry pass (to get into a play), they'd jump out and match up in a straight man-to-man," said Morley.

It takes unique personnel to try such a gamble, since it has the potential to lead to nasty matchups. For instance, at various times, Notre Dame's high scorer, Kelly Tripucka, had to defend man-to-man against every Maryland player except center Buck Williams.

Folks at courtside were in a quandary trying to figure out all the exotic adjustments that Phelps was apparently making in his defensive assignments. In fact, he wasn't making any. As long as one of his two big men, Orlando Woolridge or Tim Andree, was on Williams, he could care less what the other matchups were.

"You've just got to do a selling job to your kids to convince them that they can do well in what might be a mismatch if you tried to use it the whole game."

As an added fillip, Notre Dame lulled Maryland into a sense of comfort in the first half by offering them a manageable mental problem. The Irish switched defenses almost every time down court, luring Maryland into thinking it was solving some puzzle for the ages. The Terps played brilliantly, especially Albert King, the central character in the Maryland offense who had 14 points at intermission and appeared on the verge of easily surpassing his career record for a TV game: 17 points.

That's when Notre Dame sprang its trap. The Irish still switched defenses almost every trip down court, sometimes tossing in a little 1-3-1 zone as an additional red herring. But, whatever the visitors appeared to be playing was a ruse. Any time Maryland needed more than about 10 seconds to get a good shot, it suddenly found itself perplexed because Notre Dame was in a fundamentally different defense.

King was the primary victim. Against a zone, he usually operates in a low post. Against a man-to-man, he roams high, or flashes through the middle.

In the first half, Maryland shot 70 percent and led, 41-38. In the second half, it was outscored, 35-29, and shot only 46 percent. King went from 14 points to four.

"The crowd was so loud in the second half that the bench couldn't help the guys on the court," said Morley. "You just have to recognize it yourself."

"They tried to confuse us," said guard Reggie Jackson, who was scoreless in 34 minutes. "In the second half, it upset Albert a little. Give them credit. They changed defenses every time you looked up."

Phelps, to his credit, tried only to praise Maryland, saying how it would be "an unknown team" in the NCAA tournament that could make the final four, "especially if they lose a few games and get shipped to some other regional, where nobody knows them too well." Despite his desire to only glad-hand Maryland, Phelps flared once when it was suggested that this had been a game short on strategy. "Oh, yeah?" said Phelps. "Ask my kids and see how much coaching I did today."

Maybe substitute guard Tom Sluby, from Gonzaga High, whose only two points on a one-and-one with a lucky 13 seconds left proved to be the winning points, put it best: "They thought they knew what we were in, but in the second half, they really didn't. They had King down low, thinking it was a zone, and we could play one man on him and slough down another."

Well, maybe that's the way Lefty wanted to play it. You can't be sure. Or maybe they were just confused.

To be sure, Notre Dame's victory had many other components. "We tried to accomplish four things and we did them all," said Phelps. "We took away some of their running game. We kept them from second-effort baskets. We made our foul shots at the end. And we didn't let them get their nose ahead in the final minutes. When you do everything you try to do and only win by three points, you've beaten a great team."

This affair exemplified the best traits of college basketball. The calling card of the college game is its potential for constantly shifting strategy. The professional game, defined by the constant parameters of the 24-second clock and the mandatory man-to-man defense, is a showcase for talent. College ball, by contrast, is a mixture of both physical and mental agility.

The crowd at Cole yesterday left after two exhilarating hours of watching those physical gifts. Is it possible, however, that it, like Maryland, had missed a subtle and decisive element in such an evenly matched battle.

Digger Phelps, one foot on the first step of the Irish bus, preparing his getaway, cracked his biggest grin.

"No comment," he said.