Australia, skippered by America's Cup champion and Olympic gold medalist Tom Slingsby, had two seconds and a third. Britain, helmed by Dylan Fletcher, had finishes of third, fourth and second in the six-boat fleet. The United States, skippered by America's Cup champion Rome Kirby, finished fourth, third and fourth.
There will be two more fleet races Sunday before the top two teams meet in a match race to determine the winner. Japan has 30 points, followed by Australia with 26, Britain 24, the United States 22, China 17 and France 16.
Australia beat Japan in the final of the inaugural SailGP regatta in Sydney in mid-February. "We know it's still only halfway, and we have to do the job tomorrow, but all the training and hard work is paying off, which feels great," said Outteridge, an Australian who has won Olympic gold and silver medals and is an America's Cup veteran.
The F50 catamarans are an updated version of the cats used in the 2017 America's Cup.