Kenyan Dickson Chumba pulled away from compatriot Sammy Kitwara and comfortably won a slow Chicago Marathon in a sweep for the African nation on Sunday.
Chumba, wearing a bright yellow singlet, clocked an unofficial 2 hours 9 minutes 25 seconds as twice runner-up Kitwara recorded his fourth consecutive top-four finish, placing 25 seconds behind.
Kenyan Sammy Ndungu took third.
World half-marathon record holder Florence Kiplagat claimed the women's race, breaking away at 40km.
The race was run without pace-setters for the first time in 26 years and it noticeably affected times and strategy on the flat, typically fast course.