Kipyegon clocked 4min 02.59sec, holding off allcomers down the home straight.
Jacob Araptany and Albert Chemutai advance to Tuesday's men's 3000m steeplechase final.
Usain Bolt, the world's fastest man, suffers a dreadful start and can only claim bronze in 9.95sec in London.
Joshua Cheptegei clinches a 10,000m silver medal at the IAAF World Championships in London.
Uganda will be fielding its biggest ever team at the biennial event
Uganda’s team of 20 runners departs for London today
Uganda won three of the four individual gold medals up for grabs
David Emong won Uganda's first ever gold at the World Para Athletics Championships.
The former World and Olympic champion caught the sparse crowd by surprise
Team Uganda is due to return home with no medal, but certainly with plenty of experience as well as lessons for the junior athletes.
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