BOSTON ” The Kenyan national anthem got its annual airplay in the Back Bay on Monday after another Boston Marathon sweep.

It was the Americans, though, who were boasting of a breakthrough.

Robert Cheruiyot finished in 2 hours, 7 minutes, 14 seconds to nip the course record by a single second, and Rita Jeptoo won the women’s race for Kenya’s fourth sweep since 2000. With five American men in the top 10 ” including Nos. 3, 4 and 5 ” the United States had its best finish since the addition of prize money in 1986 helped bring back the top international fields.

“It’s exciting to see a lot of American guys run well,” said Olympic silver medalist Meb Keflezighi, who was third behind Cheruiyot and Kenya’s Benjamin Maiyo. “The crowd was just phenomenal. When they were chanting, ‘Go USA! Go Meb! Go USA!’ I was like, ‘I’m glad I’m here.”‘

Keflezighi, a naturalized citizen from Eritrea who lives in San Diego, ran with the leaders until the 16th mile and then began falling behind. Brian Sell, from Rochester, Mich., was fourth, catching Alan Culpepper around the last turn before the Copley Square finish.

“When Brian went by me, I thought he was some guy that jumped on the course,” Culpepper said, evoking memories of 1980 shortcut-taker Rosie Ruiz.

“We don’t talk about this anymore here,” moderator Frank Shorr joked.

Culpepper, from Lafayette, Colo., was fourth last year, a performance that matched the best U.S. finish since 1987. The last American to win in Boston was Lisa Larsen-Weidenbach in 1985; no American man has won since Greg Meyer in 1983, and 12 times since then there have been no Americans in the top 10.

“For those of us who are in it and make our profession, we’re probably not as surprised as other people. We’ve seen this coming for a while. We’ve seen this building,” Culpepper said. “I think it is a new day, for sure.”

Cheruiyot and Jeptoo each claim an olive wreath, a bowl of beef stew and a $100,000 first prize. Kenyan men have won 14 of the last 16 Boston titles and its women have won three in a row and six of seven.

“I think we’d given in to the fact that the East Africans are supposed to dominate the race,” said Kevin Hanson, whose club in Rochester, Mich., trained seven of the top 22 men’s finishers. “And we haven’t come up with a reason why.”

Four of Kenya’s women’s titles belong to Catherine Ndereba, who was not in the field this year. Defending men’s champion Hailu Negussie dropped out just after the halfway point with stomach problems that usually indicate dehydration.

Cheruiyot had no such troubles. He let Maiyo set a blistering pace and ran off his shoulder before taking the lead going up one of the Newton Hills. He came onto Boylston Street ” the last stretch ” with almost a minute to break the record, then sprinted the last 50 yards as volunteers waved for him to hurry.

“I think, ‘No,”‘ he said. “And then I see I can make it.”

Cheruiyot was a second faster than fellow Kenyan Cosmas Ndeti was when he set the course record in 1994 and 66 seconds ahead of Maiyo. Jeptoo, who won in Stockholm and Milan in 2004, had never run a marathon on American soil and almost didn’t make this one because of a lost passport.

She didn’t get to town until Friday and never had a chance to drive the course, let alone run it. But she outkicked Latvia’s Jelena Prokopcuka to finish in 2:23:38 and win by 10 seconds, the closest women’s finish ever; Japan’s Reiko Tosa was third, another 23 seconds back.

For the sixth straight year, Ernst Van Dyk of South Africa won the wheelchair division in 1:25:29. Edith Hunkeler of Switzerland won the woman’s wheelchair race in 1:43:41.

The official field of 22,517 entrants is the second-largest in Boston Marathon history, representing 94 countries and all 50 states.

The winners also moved to the top of the standings of the new World Marathon Majors, a circuit that will hand out $1 million in bonuses for top performances in five races over two years. Points are awarded for top five finishes, meaning three American men made the leaderboard.

“I think we’re doing something right. Quite clearly,” said New York City Marathon director Mary Wittenberg. “This is a monumental shift in where we’ve been, and a great precursor for the future.”