A flubbed final handover cost the United States gold in the men's 4x100 meter relay on Saturday as Canada surged down the final straight to take the world title.
The Americans looked set to retain their crown until the last changeover between Elijah Hall and Marvin Bracy, who lost time with a slow exchange.
Canadian anchor Andre De Grasse did not waste the opportunity and passed Bracy on the final leg, crossing the finish in 37.48 seconds.