RIO DE JANEIRO - Australia's women, powered by sisters Bronte and Cate Campbell, beat the United States and Canada to win the Olympic 4x100 meters freestyle relay in world record time on Saturday, retaining the title they won in London four years ago.
The Australians, leading off with Emma McKeon and Brittany Elmslie swimming the second leg, clocked three minutes, 30.65 seconds, beating the old mark of 3:30.98 they set in Glasgow in 2014. The United States took silver and Canada bronze.
The medal came on top of a win for Mack Horton in the men's 400 freestyle and marked a dream start for the Australians after a disappointing London Olympics four years ago when they slumped to their worst medal haul in 20 years.
After one day of competition in the Rio pool, Australia have already doubled their tally of golds from London.