Kenya's Geoffrey Mutai won the Boston Marathon men's race in an unofficial world-record time of two hours, three minutes and two seconds.
The previous world best of 2:03:59 was set by Ethiopia's Haile Gebrselassie in Berlin on 28 September 2008.
But Mutai's run does not qualify as an official world record because the historic Boston course is run from point to point downhill and he benefited from a strong tailwind.
The 29-year-old beat fellow countryman Moses Mosop by just four seconds.
And Mutai smashed the course record by almost three minutes.
Alistair Cragg made his marathon debut in the race but failed to finish, pulling out before half way when he was on a 2 hour 10 minute schedule had he maintained his early pace.
There was also a sprint finish in the women's event, where Caroline Kilel, also representing Kenya, finished two seconds ahead of American Desiree Davila.
