Kenyan Evans Rutto picked himself off the floor to win the men's Flora London Marathon in a time of two hours, six minutes and 20 seconds.
Rutto fell with compatriot Sammy Korir three miles from the finish but he got up to make a successful break on the Embankment.
Korir finished 28 seconds behind Rutto with last year's world champion Jaouad Gharib of Morocco third in a personal best 2mins 7.12secs.
In the women's race, highly-fancied Margaret Okayo turned what at one stage appeared to be certain defeat into an easy victory.
Okayo, who set off very quickly and appeared to have ran herself to a standstill, was passed in the cold and wet conditions by Romanian Constantina Tomescu-Dita just before the 11-mile mark.
But the diminutive Kenyan, twice a winner in New York, recovered to regain the lead at 20 miles to win comfortably in a time of two hours 22 minutes and 36 seconds.
Lyudmila Petrova of Russia, fifth in last year's race, challenged strongly in the final stages to overtake Tomescu-Dita for second place.
PA