(Adds comments from winner)
By Scott Malone, Svea Herbst-Bayliss and Richard Valdmanis
BOSTON, April 21 (Reuters) - Meb Keflezighi on Monday became the first U.S. male athlete to win the Boston Marathon in three decades as onlookers chanted "USA! USA!," an emotional performance in a city still recovering from last year's fatal bombing attack.
Keflezighi, who was born in Eritrea but is now a U.S. citizen, pulled ahead of a pack of elite African runners a little more than halfway into the race and held off a late challenge by Kenya's Wilson Chebet to finish in two hours, eight minutes and 37 seconds.
Among the women, Kenya's Rita Jeptoo notched her second consecutive win of the race, smashing a 12-year course record with a blistering time of two hours, 18 minutes and 57 seconds, reeling in American Shalane Flanagan, who had set a punishing pace as she led the women for the first 20 miles of the 26.2-mile (42.2-km) race.
"This is probably the most meaningful victory for an American, just because of what happened here last year," Keflezighi told reporters after his win. "Up till now I'd say my career was 99.9 percent fulfilled. Today I'd say it is 110 percent fulfilled."
Noting that the Boston Red Sox's World Series championship last year had lifted the city's spirits, he added that he wanted to provide a similar boost: "When the Red Sox did it, I said, 'I want to do it for Boston.'"
Flanagan, who finished seventh, said she had decided to run this year's race immediately after last year's attack.
"I just wanted to send a message that I was not afraid to be back here and I was not afraid to be a part of this day," said Flanagan, who vowed to return next year, and to keep returning until she notched a victory.
Last year, three people, including an 8-year-old boy, were killed and 264 were hurt when, prosecutors say, a pair of ethnic Chechen brothers left homemade bombs at the crowded finish line, tearing through the crowd.
Fans had packed the course, waving American flags and wearing T-shirts bearing the "Boston Strong" motto the city adopted as a rallying cry after last year's attack. Their screams grew deafening as Keflezighi tore through the final miles.
"It is very symbolic that an American won this race today one year after the bombing, said Veronica Carroll, who had traveled from New Jersey to watch her husband run. "It represents the strength of our country."
Some 35,755 runners from 96 countries competed in the second-largest field in history for the 118th running of the Boston Marathon.
Among the women runners, Buzunesh Deba of Ethiopia was second and compatriot Mare Dibaba third. They too turned in faster performances than the previous course record of 2:20:43 set in 2002 by Margaret Okayno of Kenya.
Among the male runners, Wilson Chebet of Kenya finished second and Frankline Chepkwony, also of Kenya, was third.
Ethiopia's Lelisa Desisa, last year's winner, did not finish, race officials said.
No American athlete has stood atop the podium on Boston's Boylston Street, not far from the site of last year's bombing, since 1985 when Lisa Larsen-Weidenbach of Michigan won the women's race. The drought has been longer for U.S. men: Greg Meyer of Massachusetts won in 1983.
Race organizers expanded the field by some 9,000 runners this year, to allow the roughly 5,000 athletes who had been left on the course last year when the twin pressure-cooker bombs went off near the finish line another chance to compete.
One of the two brothers who are accused of the bombing died after a shootout with police a few days after the blasts while the other, 20-year-old Dzhokhar Tsarnaev, is awaiting trial. If convicted, he may face execution. (Reporting by Scott Malone; Editing by Bernard Orr, Sofina Mirza-Reid and Jonathan Oatis)