Navy, behind Kevin Sinnett and Bruce Grooms, built a 20-point lead, withstood an American University awakening and registered an 89-78 victory in the opener of Capital Centre's tip-off doubleheader last night.

AU came within five points late in the game before Navy closed out its second victory against no defeats. Sinnett scored 30 points for the Midshipmen and Grooms 18.

Stan Lamb of AU led all scorers with 32 points, but Eagle forward Boo Bowers was held to eight.

Navy had little trouble solving American's full-court press and the Midshipmen were superior on the backboards.

The Mids began to break open the game in the final four minutes of the first half with a 11-2 spurt for a 47-35 lead. The Mids continued to roll at the start of the second half, leading by 20 points, 65-45, midway through the half.

Navy's offense operated fluently and produced 60 percent shooting in the first half. AU's strategy was to overplay Navy star Kevin Sinnett and keep the ball away from him, hoping other Mids would not be accurate from long range.

But the Eagles could not keep the ball away from Sinnett, who had 22 points in the second half, and the Mids were terrors from the outside, especially guard Bruce Grooms, who made six of seven first-half shots, four from 20 feet.

Navy outplayed AU inside, the Eagles starting from line getting onlyseven points and four rebounds in the first half. Boo Bowers, AU's star forward, was a non-factor, contributing only one basket and two rebounds in 16 1/2 minutes.