What Bill Lawder accomplished in 36 miles, Patricia McGovern managed in only four. Each waited until the closing stages of a race before kicking to victory on a cool, overcast morning.

Lawder, 37, had just enough strength left to struggle past David Horton in the last 400 meters of the National Capital 36-Mile road race yesterday. His winning time of 3 hours 44 minutes 34 seconds was only 13 seconds faster than Horton.

McGovern needed only the last mile of the Hecht's/9 West Women's Four-Miler to sprint to a 21-second victory over Carey Hill in 23 minutes 11.3 seconds.

For Horton, 34, a physical education teacher at Liberty Baptist College in Lynchburg, Va., the runner-up finish could not have been any more disheartening. Last year, he made up nearly seven minutes on the leader in the last five miles, but still finished second, more than 4 1/2 minutes off the winning time.

Yesterday, he allowed Henry O'Connell to gain a five-minute lead. O'Connell maintained a 5:40 pace from Alexandria to Mount Vernon and back, passing through the first 20 miles of the race in record pace. But at mile 21, O'Connell dropped out after developing cramps in both calves a mile earlier. The race became a contest between Horton and Lawder, who had been trailing Horton by about 50 seconds since the 11-mile mark.

"I knew David was a good runner, and I wanted to keep contact," said Lawder, who has run the race five of the past six years and finished second in 1980. "The way O'Connell went out, there wasn't anything I was going to do about it. At this kind of distance, you really have to run your own race."

Lawder chipped away at Horton's lead between the 31-mile point and the finish. Eventually, he whisked past Horton rounding the final corner of the course, with a quarter-mile straightaway left. Horton did not respond.

"O'Connell probably pulled us (Lawder and Horton) out a little bit fast," said Lawder, an ultramarathoner from Yardley, Pa. "At the finish, we were really struggling."

Jack Cleland, 27, of Cambridge, Mass., improved his 1983 fourth-place finish by taking third in 3:48:31. Mel Williams, 47, of Virginia Beach, ran eight minutes better than last year, earning his second straight masters title and placing fourth overall in 3:49:07. He also led his team, the Tidewater Striders, to victory.

Kay Moore, 42, of Denver was the first woman, posting a 4:52:48. Linda Belton of Roanoke followed in 5:16:30.

For the first time in the 10-year history of the race, a 20-mile race was included. Peter Nye of Arlington won the men's division by nearly six minutes in 1:55:40. Barbara Frech of Arlington was the first woman, edging Betty Blank of Falls Church by 14 seconds in 2:16:19.

Earlier, at the second Hecht's/9 West Women's race, Hill grabbed an early lead with a 5:30 first mile and was chased by McGovern and 200 starters until McGovern drew even at the three-mile point. Without hesitation, McGovern raced past Hill and opened a 50-meter margin as she glided down the last hill toward Washington's Southwest waterfront. Mary Ellen Williams, 38, of Darnestown trailed Hill by nearly 100 meters and ended third in 23:53.

"Three people went out fast at the start and I thought it was going to be a fast race," said McGovern, a 21-year-old Washington resident who ran 25th at the Paris Marathon two weeks ago. "But they slowed down. At mile three, I felt good. I picked up the pace and she fell off."