Teenager Katie Ledecky made it three gold medals at the Rio Olympics, leading the United States to victory in the women's 4x200 metre freestyle relay.
Ledecky, 19, combined with Allison Schmitt, Leah Smith and Madeline Dirado to comfortably win the event on Wednesday.
For Ledecky, it added to the golds won in the 200m and 400m freestyle at these Games. She also has the individual 800m freestyle event to come.
Australia's quartet of Leah Neale, Emma McKeon, Bronte Barratt and Tamsin Cook won silver, almost two seconds adrift, as they held off bronze medallists Canada.
Schmitt (1:56.21), Smith (1:56.69) and Dirado (1:56.39) left Ledecky with 0.86 seconds left to make up on Cook, but the American left the Australian behind over the final 100m to bring home the gold with a split of 1:53.74.