London - Allyson Felix won her 15th world career medal on Saturday as the United States won the women's 4x100 metres relay.
The Americans timed 41.82 seconds with 100m world champion Tori Bowie bringing home the baton.
Great Britain took silver in 42.12sec with Jamaica third in 42.19sec.
Felix's gold takes her to the all-time leader in terms of world medals - one ahead of Jamaican duo Merlene Ottey and Usain Bolt.
Bolt can equal the mark when he runs in the men's 4x100m relay later on Saturday.