American University turned in a sparkling defensive effort and snapped Navy's nine-game undefeated string at Halsey Field House, 70-68, tonight.

The Eagles, now 12-11, got excellent performances from reserves Brad Greenberg, Carrold Holmes and Cleo Wright, lowing a Howie Lassoff 10-foot bank

American held a 63-62 advantage folshot with three minutes to play.

The Midshipmen had a chance to regain the lead in the seasaw battle but Hank Kuzma missed free throws with 2:46 remaining.

The Eagles then elected to run some time off the clock. A minute and 36 seconds ticked away before Greenberg found a small opening in the four-corner offense and dashed past Vic Smith for a layup and a three-point advantage, 65-62.

Butch Slappy and Wright sank free throws in the final minute to stave off Navy's desperation bid.

Kuzma, who led all scores with 16 points, tipped in the game's final basket with two seconds left. It failed to solften the blow for Navy, which dropped to 11-10 for the season.

Defense was what it was all about in the first half. Both teams employed sticky man-to-man defenses, coupled with a little holding and some shoving, each forcing the other out of basic offensive patterns.

Despite the Eagles' surprisingly effective defense, patient Navy converted 15 to 26 from the floor. Kevin Sinnett sank his first three attempts and reserve sophomore Jack Stumborg added two long jump shots, sending the hosts ahead 16-10 with eight minutes gone.

American, limited to a single-shot, missed 11 consecutive tries during a four-minute stretch.

In came the Eagles' Mr. Musle, Carroll Holmes, and Sinnett cooled. The Middies leading scorer, 15.6 points, managed only one more basket in the first half. He was shadow boxed by Holmes, 6-foot-3 junior who also contributed two baskets, helping American into contention.

Brad Greenberg took a little sting out of Navy in the final two minutes, providing three straight long shots. The Eagles led, 32-30, at intermission.