BOSTON -- Kenyans are back on top of the Boston Marathon, reclaiming a winning tradition that's now as much a part of the race as Heartbreak Hill.

Rodgers Rop won the men's event Monday by three seconds over Christopher Cheboiboch, and Margaret Okayo set a course record for women in beating two-time defending champion Catherine Ndereba.

All are from Kenya, whose 10-year winning streak among men was broken last year by Lee Bong-ju of South Korea, who was fifth Monday and the first non-Kenyan to cross the finish line.

"The Kenyans are very happy. Last year, I was not happy," Rop said. "Before running, I said, 'We have to reclaim our title.' It's become a tradition in Kenya to win Boston, so I had to try my level best to win."

As he crossed the finish line, Cheboiboch embraced Rop.

At that same spot about 2 1/2 hours earlier, four American flags -- each 45-by-90 feet -- were held horizontally by volunteers in the first Boston Marathon since the Sept. 11 terrorist attacks.

Just before the 26.2-mile race that is held each year on Patriots Day, about 17,000 runners gathered near the red, white and blue starting line in overcast Hopkinton west of Boston. A state trooper sang the "Star-Spangled Banner," then ran the race.

The race began in cooler temperatures than expected and it became clear there was an excellent chance the Kenyan national anthem would be played at the end.

"I just feel proud when I hear that national anthem being played," Ndereba said after she embraced Okayo. "And if it was not for me, it's for Margaret."

Rop finished third in his only other marathon, in New York last November. Okayo won the women's race there.

Her winning time Monday was 2 hours, 20 minutes, 43 seconds, beating Uta Pippig's course record of 2:21:45 set in 1994. Ndereba finished in 2:21:12.

Rop won in 2:09:02. Cheboiboch's time was 2:09:05. They were followed by Kenyans Fred Kiprop and Mbarak Hussein. Both finished in 2:09:45.