RIO DE JANEIRO - The opening day of action at the 2016 Olympics ended in style, with Australia winning the women's 4x100m freestyle relay in a new world record time of 3 mins 30.65sec.
Boasting the two fastest sprinters in sisters Cate and Bronte Campbell, Australia took gold ahead of the United States (3:31.89) and Canada (3:32.89) at the Olympic Aquatics Centre.
In the process, they rewrote their own world mark of 3:30.98 - set at the 2014 Commonwealth Games.
Reigning 100m free world champion Bronte, 22, was not part of the Australian team that won this event in an Olympic record time of 3:33.15 four years ago in London.
But she helped Australia break the Games record in qualifying (3:32.39) on Saturday.
Australia found another gear in the final, allowing Bronte and Cate, the 24-year-old 100m free world record holder, to celebrate their first Olympic relay gold together.
"Definitely my favourite race ever, in an Olympic final with my sister and two girls I have known since I was 12,13 years old and a gold and a world record," said Bronte. "You can't ask for more."
Emma McKeon and Brittany Elmslie, both 22, completed the quartet.