Once, twice, three times a champion, Bill Rodgers made his move to the front on the treacherous hills of Newton and flew away from the field to break his American record in winning the Boston marathon today.

It was a raw, rainy Patriots Day, and Rodgers had trouble with his contact lenses at the start, wiht tightening legs at the midway point and with a tummy in turmoil the last 10 miles.

"I had to go to the bathroom," he said after leading the fastest field in the 83-year history of the event.

Rodgers, who won Boston a year ago, was clocked in 2:09.27, beating by 28 seconds the record he set when he won his first Boston in 1975.

At the end, Rodgers, described by early leader Tom Fleming as "the greatest marathoner in history," was two full city blocks ahead of his closest pursuer, Japan's Toshihiko Seko, timed in 2:10.12 over the 26-mile, 385-yard course.

Joan Benoit, 21, a senior at Bowdoin College in Maine, running her second marathon and first Boston, won the woman's competition, also in record time. She shattered the women' course mark by more than seven minutes and the American mark by 68 seconds, also moving to the front for good on the Newton hills and finishing in 2:35.15.

When Rodgers heard her time, he slapped himself in the face, beamed, and told Benoit. "You're a marathoner now ...unbelievable."

Most of Rodgers' competitors were saying the same thing about him. This slight, 31-year-old former schoolteacher from Melrose, Mass., who ran wearing his patented painter's gloves and a knit wool cap, demonstrated once again that he is the dominant figure in the most grueling sport of all.

"Most of the time, I didn't think I could win," Rodgers said. "But when it started to thin out (at 15 miles), I started to think I had a shot. And when I think I have a shot, I can be very tough.

"Now, only one thing is missing, and if can win that, I'll retire-a medal in the Olympics."

At the start, Rodgers had trouble with a contact lens that took several minutes to adjust. Through most of the first half of the race, he needed that lens to focus on the early leaders-Fleming and Kevin Ryan of New Zealand.

At Wellesley College, the halfway point in the race, Fleming held an 80-yard lead but was beginning to fade, along with Ryan.Rodgers was in a pack of a dozen runners at the point, bidding his time and hoping the ache in his legs would go away.

It did.

Minnesotan Gary Bjorklund took the lead from Fleming at the 15-mile mark, maintaining a 20-yard advantage over a smaller pack that included Rodgers and Seko.

Bjorklund held on until the Newton City Hall, 19.7 miles into the race. There, Rodgers and Seko moved ahead going into the Newton hills that finish with a half-mile climb called "Heartbreak."

At that point a year ago, Rodgers made his big push, and today he pushed it once again. At the bottom of Heartbreak, he had a 15-yard lead. At the top, he had stretched it to 40, and Seko was wasted.

"The first time I thought about winning was coming down Heartbreak," Rodgers said. "I had a 40-yard lead and I said to myself, 'Maybe I've got it today.'"

There was never any doubt the rest of the way, although Rodgers had to slow for a moment at the 21-mile mark when a mounted policeman's horse backed onto the course. It was quickly reined under control and Rodgers was on his way again.

As he breezed past the running-supplies store he owns at Cleveland Circle, four miles from the finish, Rodgers was leading by 80 yards. He responded with smiles and an occasional wave to the smaller-than-usual crowds kept down by the rain, the cold and the new law that raised the Massachusetts drinking age from 18 to 20.

At the finish, Rodgers was surrounded by a half-dozen beefy Boston policemen as he was escorted to the victory stand. Before he got there, however, Seko crossed the line and the two embraced.

In the interview area, Seko, speaking through an interpreter, said he had hoped to stay with the pack and challenge Rodgers the last six miles.

"But when he wanted to, he lacked the spark," said the interpreter.

Then someone asked Seko if the rain and cold had bothered him.

"No," he said, "but this is Bill Rodgers weather."

Benoit also prospered in the wet.

After running the first mile at a 5:40 pace - "Disastrous for me," she said - Benoit was content to play follow the leaders - Patti Lyons of Quincy, Mass., and Gail Olinek of Fort Lauderdale, Fla. - through the midway point of the race.

On the Heartbreak, Benoit finally passed Lyons and took the lead.

"I ran with her for awhile," she said, "and I kept my pace. Pretty soon, she dropped back and I didn't see her again. To tell you the truth, I really don't believe I'm here.

"Beginner's luck, maybe."

Benoit's previous marathon was a 2:50 effort two months ago in Bermuda. She once held the women's world record for 10 kilometers and has a better reputation on the track than on the road. Or had until today.

She was forced to cut short her postrace interviews because of pains that left her close to tears as wave of media people surrounded her, ignoring her pleas to "Please, just get me to a hot shower."

Later, she had another request.

"I hope I get a few extensions on my college term papers," she said.

Certainly, she earned them.

Robert Hodge, along with Rodgers one of four members of the Greater Boston Track Club in the top 10, finished third in 2:12.30, with Fleming rallying to fourth in 2:12.30 and Bjorklund taking fifth in 2:13.14...Patti Lyons was the second woman in 2:38.22, with Susan Krenn of San Diego 2:38.50...Bruce Robinson of Silver Spring, Md.,was the top Washington-area finisher, placing 48th in 2:19.03.

A total of 7,800 runners were officially entered, but estimates for the number of men and women who took the line at the start in Hopkinton ranged as high as 12,000...One of those starters was Steve Marek, of Millwood, N.Y., who dressed as Superman.

"I ran 14 miles in the Marathon until I stepped in a pothole," he said. "Then I took a bus home. Why do I run? To fly faster, why else?"

THE TOP 50 FINISHERS

1, William Rodgers, Melrose, Mass., 2:09.27; 2, Toshihiko Seko, Japan, 2:10.12; 3, Robert Hodge, Hanover, Mass., 2:12.30; 4, Tom Fleming, Bloomfield, N.J., 2:12.56; 5, Garry Biorklund, Minneapolis, 2:13.14; 6, Kevin Ryan, New Zealand, 2:13.57; 7, Bobby Doyle, Central Falls, R.I., 2:14.04; 8, Randy Thomas, Wellesley, Mass., 2:14.12; 9, Herman Atkins, Everett, Wash., 2:14.27; 10, Richard Mahoney, Weymouth, Mass., 2:14.36.

11, Jerome Drayton, Toronto, 2:14.47; 12, Dean Matthews, Clemson, S.C., 2:14.48; 13, Don Grels, New Zealand, 2:14.49; 14, Chris Stewart, New York, 2:14.56; 15, Tony Sandoval, Eugene, Ore., 2:15.23; 16, Duncan MacDonald, Mountain View, Calif., 2:15.28; 17, Jeff Norman, England, 2:15.44; 18, Esa Tikkanen, Finland, 2:16.

19, Nobusaki Takao, Japan, 2:16.10; 20, Frank Richardson, Ames, Iowa, 2:16.20; 21, Gunter Mielke, West Germany, 2:16.30; 22, Oscar Miranda, Tampa, Fla., 2:16.31; 23, Colin Kirkham, England, 12:16.34; 24, Steven Palladino, San Mateo, Calif., 2:16.41; 25, William Sieben, Rahway, N.J., 2:16.44; 26, John Lodwick, Eugene, Ore., 2:16.46; 27, David Babiracki, Granada Hills, Calif., 2:16.49; 28, Dick Hooper, Alhambra, Calif., 2:16.50; 29, Ron Wayne, Alameda, Calif., 2:17.02.

30, Richard Sayre, Akron, Ohio, 2:17.17; 31, Curtis Alitz, West Point, N.Y., 2:17.25; 32, David Harper, San Diego, Calif., 2:17.31; 33, Trevor Wright, England, 2:17.35; 34, Tim Nickevich, Berkley, Calif., 2:17.38; 35, Lee Fidler, Stone Mountain, Ga., 2:17.44; 36, Scott Wyatt, Toluca Lake, Calif., 2:17.48; 37, Kevin McCarey, Eugene, Ore., 2:17.50; 38, William Gavashan, Indianapolis, 2:18; 39, Keith Brown, Newtonville, Mass., 2:18.04.

40, Thomas Howard, Surrey, Canada, 2:18.09; 41, Kenii Takami, Japan, 2:18.10; 42, Robert McOmber, Bowling Green, Ohio, 2:18.15; 43, David Clark, England, 2:18.28; 44, Clifford Carthauser, Lincoln, Neb., 2:18.31; 45, Walter Saegar, Dayton, Ohio, 2:18.40; 46, James Rafferly, Flushing, N.Y., 2:18.54; 47, Kerk Lazaridia, Bolton, England, 2:18.57; 48, Bruce Robinson, Silver Spring, Md., 2:19.03; 49, Evin McDonald, Greenville, S.C., 2:19.10; 50, Falko Will, Germany, 2:19.23.

TOP 15 WOMEN

1, Joan Benoit, Cape Elizabeth, Maine, 2:35.15, 2, Patti Lyons, Boston, 2:38.22; 3, Susan Krenn, San Diego, 2:38.50; 4, Elizabeth Hassell, Australia, 2:39.48; 5, Susan Petersen, Laguan Beach, Calif., 2:43.02; 6, Kim Merritt, Racine, Wis., 2:44.28; 7, Cynthia Dalrymple, Seattle, Wash., 2:45.30; 8, Karen Doppes, Cincinnati, 2:45.45; 9, Gail Olinek, Fort Lauderdale, Fla., 2:47.36.

Alson, 10, Lauri McBride, New York, 2:47.37; 11, Derrie Lewis, Solano Beach, Calif., 2:48; 12, Susan Hughes, Wellesley, Mass., 2:48.26; 13, Laurie Binder, San Diego, 2:48.35; 14, J. Gumbs-Leydig, San Mateo, Calif., 2:48.44; 15, Marilyn Bevans, Baltimore, 2:49.56. CAPTION: Picture 1, Bill Rodgers approaches the finish line in the 83rd Bostonmarathon, winning the prestigous race for the third time and setting anAmerican record of 2:09.27. AP; Picture 2, no caption; Picture 3, The main street of Hopkinton, Mass., is awash with runners as the 83rd Boston marathon starts. At the finish (above), Bill Rodgers celebrates. Massachusetts Gov. Edward King is behind him. UPI