 He gained selection for the 2011 World Championships in Athletics and came fifth for Kenya in the men's 10,000 m. That year, Mathathi set a course record for the Great North Run half marathon, finishing in a time of 58 minutes 56 seconds.Two weeks later he also won the Great Edinburgh Run 10K in course record time.At the start of 2012 he finished second at the Chiba Cross Country meet.