Versatile swim veteran Emma McKeon has made a slick start in her quest to join Australia's Olympic icons.
Three Australians - Shane Gould, Ian Thorpe and Alicia Coutts - have collected five medals at a single Olympics; none has won more.
But McKeon is eyeing a seven-medal haul with her bumper program beginning with an ominous Saturday night swim.
McKeon was equal-fastest in the 100-metre butterfly heats, dead-heating with China's world No.1 Zhang Yufei, as Australia's feted swim team opened their campaign at the Tokyo Aquatic Centre.
Australia's women's 4x100m freestyle relay team - seeking a third consecutive Olympic title - cruised into Sunday's final as a 21-year-old Victorian emerged as a surprise gold medal contender.
Brendon Smith clocked an Australian record in the 400m individual medley heats to be fastest into Sunday's final.
Smith's stunning swim came as the host nation's hero, reigning medley world champion Daiya Seto, flopped and failed to make the medal race.
Australia's dominance of the women's freestyle relay continues despite the absences of McKeon and flagbearer Cate Campbell in the heat team.
Mollie O'Callaghan, Meg Harris, Madi Wilson and Bronte Campbell still booked lane four, in a time almost two seconds ahead of the next-best, the Netherlands.
Australia's star attractions McKeon and Campbell, who hold the fastest 100m freestyle times in the world this year, will race in Sunday's final with Wilson and triple Olympian Bronte Campbell.
McKeon's relay final will follow her 100m butterfly semi-final, with compatriot Brianna Throssel sneaking into those semis as 16th qualifier.
In the men's 400m freestyle, Australians Elijah Winnington and Jack McLoughlin dead-heated for first in their heat - they're equal-fourth quickest into Sunday's final.
Australia's two 100m breaststrokers, Zac Stubbelty-Cook and Matt Wilson, couldn't advance from their heats.
Australian Associated Press