Australia has completed a golden first night in the pool at the Rio Olympics, with two stunning legs from the Campbell sisters setting up victory in the 4x100 metres freestyle final and breaking the world record.
The previous world record of 3:30.98 had belonged to Australia, with the Campbell sisters among the quartet that set that mark at the Commonwealth Games in Glasgow 2014.
"It doesn't get better than that," Bronte said.
"There is nothing better than this in our sport, this is it, and I can't believe we finally achieved it after all these years of dreaming of it.
The victory gave Australia not just consecutive 4x100m freestyle relay gold, but its fourth in total in the event, with wins also coming in 1956 and 2004.
"Everyone is just pulling together we've got a great team, a great support team," Cate said.
"We've got a great vibe going and hopefully this will kicking the momentum off and we'll get the ball rolling with this."
Silver medallist United States had led Australia through the opening 100 metres, with Simone Manuel edging ahead of McKeon courtesy of a slim margin of .05.
Abbey Weitzel, however, put some distance between the Americans and Australians with a scintillating second leg to establish a .61 advantage at the halfway point.
Elmslie handed over to Bronte for Australia and the complexion of the race changed considerably when the reigning world 100m freestyle champion cut down Dana Vollmer to trail by just 0.07 at the 250-metre mark.
Bronte powered ahead and handed older sister Cate a decisive lead worth .42 and the older of the siblings merely finished the job in the final 100 metres.
Cate moved further in front to touch the wall a staggering 1.24 seconds ahead of US distance star Katie Ledecky, who will have plenty of opportunities to add to her gold tally at the Rio Games.
Canada was third in 3:32.89.