Olympic champion and race favourite Steven Gardiner of the Bahamas pulled up injured in his world championship 400m semi-final on Tuesday and failed to progress to the final.
Gardiner, the 2019 world champion and fastest in the world this year, was well-placed coming off the final bend but stopped, grimacing in pain clutching the back of his leg.
Former Olympic and world champion Wayde van Niekerk was the chief beneficiary as he advanced as a fast loser.
Jamaica's Antonio Watson was the fastest qualifier with a personal best 44.13, while Briton Matthew Hudson-Smith set a European record of 44.26 winning his heat.
