The 2006 world indoors champion led Saturday's final from near the start to the finish, crossing in 1 minute, 44.65 seconds.
Ismail Ahmed Ismail of Sudan took silver in 1:44.70 and reigning world champion Alfred Yego of Kenya got the bronze at 1:44.82.
Defending champion Yuri Borzakovsky, world indoor champion Abubaker Kaki and Olympic silver medalist Mbulaeni Mulaudzi all failed to make the final.