A lead pack of eight runners glided through the first two miles of the Georgetown 10-kilometer road race -- running consecutive miles of 4:42 and 4:43 -- yesterday before turning onto Reservoir Road and doing a mile uphill. Then the real racing began.

Four devastating Georgetown hills later, former George Mason runner Dave McCormack sprinted from 31st Street onto M Street, three-tenths of a mile from the finish, catching his only remaining rivals, Gerry Clapper and John Glidewell, by surprise and winning in 29:48, a course record by 10 seconds.

Fifty yards from the finish, Glidewell began to close on McCormack and, "if it was another 50 yards longer, I would've made it," Glidewell said. He fell short by a second, 29:49, four seconds ahead of Clapper.

Sally Strauss, a law clerk in her final tune-up before the Marine Corps Marathon, in which she'll try to qualify for the Olympic trials, led the women from the start, winning in 36:08.

With 3,200 runners entered, 500 more than previous years, Strauss never saw another woman, pacing herself with the men around her. Carey Hill of Arlington was second (36:30) and Patricia Bullinger of Arlington third (37:20).

Through the first two miles, the course had descended gradually from the start in front of J. Paul's Restaurant on M Street. When Jim Hage, Clapper, McCormack, John Wessels, Glidewell and Joseph Kipsang started up Reservoir, it would be the last they'd see of easy terrain until the finish. Kipsang was the first to fade, losing 10 yards that quickly became 50. The rest of the group went through the third mile in 5:13 and within a half mile Wessels and Hage fell off the pace.

Glidewell, 30, was testing his speed in his last race before the Columbus Marathon in Ohio, where he will try to qualify for the 1988 Olympic trials marathon.

"I've got a little girl now, a 3-year-old," he said. "I've qualified twice before but never run and this time I decided to try and have her watch. I don't know if she'll understand, but it'll be nice later when she can say she watched her father run an Olympic trials."