Norman Green of Wayne, Pa., became the first American 50 years old or over to win a national masters championship race yesterday, setting his fifth U.S. age-group record in six months as he won the TAC National Masters 20-kilometer on a rain-soaked course at Hains Point.

Green, 50, completed the 12.4-mile race for runners age 40 and up in 65 minutes 50 seconds, breaking the age 50-54 record of 66:15 set by Ray Hatton in Oregon last year.

Tony Gerrity (66:03) of Devon, Pa., George Keim (66:24) of Waynesboro, Pa., and Herb Lorenz (66:28) of Willingsboro, N.J., followed Green yesterday.

In the women's race, Susan Henderson of Boulder, Colo., defeated runner-up Lolitia Bache of Annandale by seven minutes, in 77:36.

A tight pack of 12 runners, led by Green, covered the first mile in 5:07, moving ahead of the field by 50 yards. Completing the first of a four-loop course, Lorenz, 44, took over the lead, with Keim, 40, on his right shoulder and Bill Hall, 42, of Durham, N.C., on his left.

Green cut the pack to eight as he bore ahead by two yards and made the midpoint in 33 minutes.

Completing 15 kilometers in 49:43, Green surged again, with Keim, Lorenz and Gerrity spread side by side and right behind. A mile and a surge later, Green and Gerrity had made it a two-man race.

With his final push, Green turned the corner with 1 1/2 miles remaining and established a 15-yard lead. Keim and Lorenz trailed by 50.

When "he turned onto the final straightaway," said Gerrity, 40, a manager of manufacturing at Wyeth International, "that's when he finally broke away from me."

Said Green, director of office planning resources for the American Baptist National Ministry, "I was surprised that Tony and I had broken away from the pack. I was trying to break the 50-54 age-group record."

Green also holds age 50-54 records for eight, 15 and 25 kilometers and 10 miles (set in the Cherry Blossom here).