The Jamaican wins gold with a world leading time while Britain’s Gemili finishes fifth.
Usain Bolt secured his third successive world title victory in the 200m with a time of 19.66 – the fastest in the event this year.
Fellow Jamaican Warren Weir claimed Silver while American Curtis Mitchell took the Bronze medal by barely a hundredth of a second.
Britain’s Adam Gemili finished fifth, only four hundredths of a second off the top three.
The 19-year was in good spirits and after the race, telling the BBC: “What an event this whole championship has been for me. There are no words to describe how I am feeling. I’m very lucky and I’m really happy.”
Bolt now has the opportunity to become the joint most decorated athlete in the championships’ history, alongside Carl Lewis and Allyson Felix, if the Jamaican team win the 4x100m final on Sunday.
The milestone would be a suitable present for the 100m and 200m world record holder, who celebrates his 27th birthday on Wednesday.