Entering the Beijing Olympic stadium Dibaba in a sprint finish held off Kenya's Helah Kiprop to the world championships title.
Dibaba crossed the line in 2 hours, 27 minutes, 35 seconds just one second ahead of Kiprop. Bahrain's Eunice Kirwa won the bronze medal finishing after 2:27:39.
The two time world marathon champion Edna Kiplagat after dropping back from a lead pack 1km to the finish settled in 5th place.
Full women's marathon results here.