When De Paul was assured victory over Notre Dame yesterday, the the athletic director of American University, Bob Frailey, looked away from the television set in his office and said: "Let's see. De Paul's only loss was to Old Dominion -- and we beat Old Dominion, on the road. That makes us No. 1 in the country."

Smiling, he turned to AU publicist Rick Vaughn. "Get the (NCAA selection) committee on the phone," he said. "They might not know that."

They evidently did not. Or that AU's record was among the 10 best in all the land. Or that its section of its league was rated tougher than the Pac-10, the Big Eight and the Southwest Conference. Or that AU has been this season's Cinderella in sneakers, as nice a sports story as the NCAA could imagine.

Yesterday, though it hardly was shattered, the American dream collided with athletic reality. Frailey, Coach Gary Williams, Vaughn and some others gathered for several hours, waiting for the phone call that never came, the one that would have meant the most money and glory in the history of AU sports.

To nearly, everyone who knows a whit about basketball, AU is among America's 48 best collegiate teams. But some of the best 48 teams do not make the NCAA playoffs, for reasons that include postseason conference tournaments and the structure of the selection committee.

"Gotta have faith," somebody said to Frailey when the hour for the phone call came and passed.

"I have faith," he said. "It's the politics I'm worried about."

The politics got 19-10 Villanova picked ahead of 24-5 American. Nine Eastern teams were selected for the NCAA tournament; the team with the best record in the East was not. In part, AU has itself and its conference to blame.

Had AU maintained the lead it held for 38 minutes the final two against St. Joseph's Saturday night, had it not been foiled by the very pressing tactics that made it so appealing all season, Frailey would have been frolicking by midafternoon. The Eagles would have been East Coast Conference champions and assured a bid.

If the ECC had one division instead of two, an East but not a West, AU might yet have made the NCAA field. When the thinkers who determine the NCAA field examined AU's schedule, they discovered league victories against some of the sorriest teams in major-college sports.

A computer study as sophisticated as any recently determined that the five toughest conferences in the country were, in order: Atlantic Coast, Big-Ten, Southeastern, Big East and ECC East. The Big East and Big Eight, with powerful friends in the proper NCAA places, have three teams each in the NCAA; the ECC has one.

And, for every AU wailing and crying foul today, there is a Howard jumping through the clouds at saving a seemingly sad season by doing what the Eagles could not: winning the conference championship and gaining entree among the NCAA elite.

Some AU faithful were grumbling about 20-11 Georgetown being selected. That is the irrational thinking that comes immediately after what you have worked so hard for goes sour. After all, the Hoyas lost to such as North Carolina, Louisiana State and De Paul and beat AU by two points.

The local irony, of course, is that the team with the best record by far, though not the best team by far, missed the NCAA tournament. Maryland all but pulled off the Eagles' wings early in the season, when Boo Bowers was healthy.

"We played our best style, which is running," Williams said. "And when teams saw how Maryland outran us that night they must have realized then to pull in their offenses. We might have been the reason some of the teams have had success against Maryland."

The phone did ring in Frailey's office yesterday. Everybody snapped to attention each time.

Williams answered one call and, with the room silent with suspense, cupped his hand over the receiver and said to Frailey: "Is the bowling alley open this afternoon?"

An anxious student called from Florida.

An anxious Frailey tried to calm his nerves once with a ludicrous scenario.

"What if they call and I say: 'No. We believe only the best ECC team should go and we'll stay in the East and go NIT'?"

He laughed, then suddenly produced a memo he had received from the NCAA two days ago that included the statement: "Congratulations on your team's entry into the 1981 National Collegiate Basketball Tournament." y

Could we find a friendly judge? somebody wondered.

"Yes, a 49-team tournament," said Ray Murphy, the assistant athletic director.

Then Frailey discovered the disclaimer, another memo that said the second one was being sent "in case" the team was selected.

AU wanted desperately to make the NCAA field as a reward for Williams and the team. There was a practical reason: $90,000. At least. Each of the 48 teams is guaranteed that much money if it loses in the first round. That is about 20 percent of Frailey's budget for all the teams at AU.

"Scary, isn't it?" he said. "And you wonder why we're worried sick about scandals."

By 3 p.m., Frailey's attitude became less cheery.

"No, it doesn't look good," he kept saying.

When NBC's Dick Enberg merrily announced the pairings would follow this important message and the nearby phone was silent, what Frailey and the rest had sensed became inevitable.

"Who could have imagined on the first day of practice, Oct. 15," said Murphy, sitting on the floor, "that we'd be here today moaning about having to accept a bid from the NIT?"

Before he left the room to be alone, to tap a letter opener on his desk in frustration, Frailey said to Murphy: "You get success -- and you always want a little bit more."