Merga, who was passed in the last quarter-mile and finished fourth in Beijing, pulled away before Heartbreak Hill and won in 2 hours, 8 minutes, 42 seconds almost a full minute ahead of Kenyas Daniel Rono and American Ryan Hall.
Kosgei won a sprint with defending champion Dire Tune, trading the lead several times in the final blocks of Boylston Street before hitting the tape less than a stride ahead of the Ethiopian in 2:32:16. American Kara Goucher led the three as they crossed the MassPike into Kenmore Square with one mile to go, but she was outkicked down the stretch and finished 9 seconds back.
The winners will take home $150,000, but Merga had to wait for his traditional laurel wreath: The womens pace was so slow and the men finished so fast that he crossed the finish line before Kosgei had a chance to climb the champions podium.
Kosgei said the weather conditions made for a difficult finish.
The wind was a bit stronger. ... So, it was very hard, Kosgei said. I decided I must try. So, I tried.
No American has won in Boston since Lisa Larsen-Weidenbach in 1985, when the U.S. women swept the top three and the men came in second and third. The 2009 race was the slowest since then, a pace that had the mens leaders passing the female stragglers and approaching the final mile as the women were hitting the tape.
Goucher burst into tears and was consoled by her husband, and Tune fell to the pavement for several minutes after the final sprint. Race spokesman Jack Fleming said Tune would not be available because she was receiving medical attention; he did not elaborate.
Gouchers voice cracked repeatedly in the postrace news conference.
I just wanted it for everybody that wanted it for me, she said. Im proud of how I did. I just wanted to be the one that won for everybody.