The crowd of 77,083 at the Coliseum, which had expected to see the end of the most competitive women's distance race in history, instead became part of a tribute to the 27-year-old Miss Benoit of Freeport, Me., the world- record holder in the event who underwent arthroscopic surgery on her right knee on April 25. Mrs. Waitz, 30, finished 1:26 behind. Rosa Mota of Portugal won the bronze medal with a personal record of 2:26:57, followed by Ingrid Kristiansen of Norway and Lorraine Moller of New Zealand.

The celebration was jolted by the most gripping sight of the day, the struggle of Gabriela Andersen-Schiess, 39, of Sun Valley, Idaho, a dual citizen of the United States and Switzerland who represented the Swiss team. She listed to her left as she appeared in the tunnel, then staggered and weaved back and forth across the track as the crowd cheered in an effort to help push her through her last lap.

More than 2 1/2 minutes passed before she completed her final 200 meters, accompanied by two members of the medical unit. She appeared to acknowledge the crowd with her right hand, not long before falling into the arms of three workers.

''As she was coming up the tunnel,'' said Dr. Richard Greenspun, the chief medical officer for athletes of the Los Angeles Olympic Organizing Committee, ''my thought was this was one of the most courageous things I'd ever seen, and we shouldn't interfere.''

She suffered from heat exhaustion and was dehydrated, but was not hospitalized. She was released in the care of the Swiss team physician. A spokesman for the Swiss Olympic Committee said she was not allowed to leave her room in the Olympic Village and was unavailable for interviews.