His victory in Stuttgart in 1993 was especially impressive as he was only aged eighteen and led the race from the front for most of the second half. On the final straight he shrugged off an attack from Haile Gebrselassie. His winning time of 13:02.75 minutes was a new World Championships record. He became the youngest world champion, aged 18 years 177 days. That same year he broke the World junior record in 5000 metres in Zurich by running 13:06.50.[1]
His gold medal in 1995 was won under very different circumstances as the final was run at a slow pace and decided in a sprint.
An accomplished road race runner, Kirui won three consecutive Bay to Breakers 12K titles, from 1993 to 1995.[3] His first victory in 33:42 set a world road record in that event.