South Africa's Stephen Mokoka, who had never run a 50km race before, broke the world record on home soil in Gqeberha on Sunday.
Mokoka, 37, crossed the finish line in two hours, 40 minutes and 13 seconds, beating the record set by Ethiopian Ketema Bekele Negasa (2:42:07) at the same event last year.
"I'm tired," Mokoka, a three-times Olympian, said. "It's a long way and I don't know how I'm going to feel later, but I enjoyed it."
Ethiopia's Amelework Fikadu Bosho dominated the women's race to finish in a time of 3:04:58, nearly four minutes ahead of the rest but 34 seconds short of the world record.