4 x 100 metres Relay, Women

This was expected to be a battle between the Jamaicans and the Americans, with Jamaica, led by 100-200 winner Elaine Thompson, favored for the gold. They won heat one easily and their task seemed easier when the US team botched the second exchange between Allyson Felix and English Gardner. The veteran Felix made Gardner retrieve the baton and finish the race, but the US finished sixth and seemingly out of the final. The US protested, howeer, that the adjacent Brazilian runner had moved out of her lane and interfered with the Americans and the protest was upheld. The US team was allowed to run a time trial later that evening and attempt to qualify on time, requiring them to use the same lane and the same team, and the US ran 41.77 to move into the final.

The unusual circumstances forced the US out of the prime inner lanes and they had to run in lane one. Tianna Bartoletta put the Americans in the lead on the opening leg and Felix held off Thompson on the backstretch, giving Gardner a tenuous lead. Gardner pulled the US ahead with a scorching turn run, allowing 100 metre silver medallist Tori Bowie to win easily, as she pulled away from 100 bronze medallist, and 2008-12 100 gold medallist, Shelly-Ann Fraser-Pryce. The US foursome ran 41.01, the second fastest time ever.