BOSTON – Joan Benoit Samuelson capped off a brilliant career of running marathons Sunday the same way she burst onto the national stage in Boston 29 years ago – wearing a Red Sox cap given to her by a spectator and crossing the finish line with an American record.

In what was likely her final marathon – at least a competitive one – the Freeport resident and Olympic gold medalist easily surpassed her own expectations at the U.S. Olympic Trials in the women’s marathon.

Starting conservatively, Samuelson finished with a flourish, completing the 26.2-mile course in 2 hours, 49 minutes, 8 seconds, the fastest time ever recorded by an American woman age 50 and over.

The previous record was 2:50:26 set by Shirley Matson in 2006.

“All I wanted to do was break three hours and to finish,” Samuelson said. “I put an immense amount of pressure upon myself coming into Boston, because I didn’t know if either was possible.”

Samuelson saluted the new generation of runners, noting how much the sport has evolved since she started running. Her time Sunday placed her 90th among the 124 finishers.

Deena Kastor, Magdalena Lewy Boulet and Blake Russell – the top three finishers, who qualified for the U.S. Olympic team – paid Samuelson the ultimate tribute by waiting at the finish line for the icon to finish. The gesture deeply touched Samuelson.

“It was an honor to be at the finish line to greet her,” race winner Kastor said. “She has always been an inspiration to me, so it was wonderful that she accomplished what she did today and set an American record. She just continues to give back to the sport day after day.”

Samuelson’s legacy includes the 1984 Olympic gold medal in the inaugural women’s marathon and two victories at Boston (1979 and 1983). A former world-record holder, her American record stood for 18 years. She still owns four of the seven fastest marathon times recorded by American women.

In addition to the torch passing among the elite athletes, a similar shift was witnessed among Maine women. Sheri Piers, 36, of Falmouth, enjoyed a breakthrough performance, picking off runners during the second half of the race to place 16th. Her time of 2:38:46 beat her previous best time by nearly seven minutes.

Emily LeVan of Wiscasset, whose focus was interrupted the past five months, while her four-year-old daughter, Maddie, was treated for leukemia, was happy with her performance. LeVan, 35, had the 10th fastest qualifying time among the runners who started the race, but she quickly dropped back, realizing her training was not up to par with her touted rivals.

As far back as 80th just past the midpoint, LeVan finished 67th in 2:45:45.

“I knew that my fitness wasn’t where I wanted it to be,” LeVan said. “I just wanted to enjoy the experience more than anything else.”

Focusing on two trials – the Olympic trials and her daughter’s trial to beat her disease, LeVan set out to raise money for cancer research. As of a few days ago, she had raised $64,185, nearly $12,000 more than her original goal of twice the marathon distance.

LeVan got emotional as she recalled the tribulations the past five months.

“It’s a great celebration of how far we’ve come,” LeVan said. “It’s been a long five months. To be able to be here, to celebrate this accomplishment and to celebrate my daughter, it’s been great.”

Kristin Barry, 34, of Scarborough, placed 73rd in 2:46:58. Former Bates College student Molly Taber of Haverhill, Mass., failed to finish.

There will be many more races for Piers, LeVan, Barry and Taber, but Samuelson’s road appears over.

Samuelson said she might still run another marathon, but not at the elite level of Boston or the Olympic trials. It would likely be as a running partner with family members or friends, she said.

“I felt very strong out there today,” Samuelson said. “It was important to finish this race. That was the most important thing, and I feel surprisingly good right now.”

Sunday’s race was the perfect bookend for a career that began in 1979. As an unknown Bowdoin College student, Samuelson conquered Boston in her first attempt, wearing the Red Sox cap during the final few miles.

The perfect ending Sunday with another Red Sox cap on her head was not planned, Samuelson insisted

“It was spontaneous, just as it was in 1979,” she said. “There’s been great years in between and not so great years – for both the Red Sox and myself.”