Australia's golden girls and shrewd team tactics have given the host nation a flying start on night one of the head-to-head swimming event with rivals the United States in Sydney.
Emma McKeon and Mollie O'Callaghan sent the parochial crowd of 3355 into raptures as they swam down the USA in the third and fourth legs of the mixed 4x100 medley relay that opened the event at Sydney Olympic Park Aquatic Centre.
Teenage swimming sensation O'Callaghan stunned McKeon to win the 100m freestyle final at the Commonwealth Games but this time followed her idol into the pool to surge past Mallory Comerford and snatch the first Duel in the Pool points for Australia.
McKeon brought six gold medals, a silver and a bronze home from Birmingham, so it was a shock when the superstar was beaten to the wall by the USA's Beata Nelson in the 3x50m butterfly skins.
It was all part of the plan for Australia as they used their 'double dip' wildcard to add another 50m race in the two-way battle, with McKeon too fast for the tiring Nelson in the extra leg to steal the points.
"I felt really bad doing that last 50, putting that extra one on for Beata," McKeon said.
"But that's just the strategy, they told me to do it so I just did it.
"It was easier for me because I knew it was coming, so I can't imagine what Beata was feeling."
Australia earned double points in the women's 4x100m freestyle after using a 'powerplay' on the event that they won gold in at the Tokyo Olympics last year, with O'Callaghan this time taking a lead into the final leg and cruising home.
Olympics and Commonwealth Games gold medallist Kaylee McKeown backed up strong times in earlier relays to take out the 100m backstroke with O'Callaghan touching home in second in her non-preferred stroke.
The USA's own emerging star Bella Sims showed her talents to take out the 400m broken freestyle that includes a 200m followed by two 100m legs, with a brief recovery period between each race.
"I train broken freestyle, because who would want to do the whole distance all the time. I think I'll do good in it," Sims said before the race.
Zac Stubblety-Cook had to settle for third in the 100m breaststroke, with his preferred event the 200m breaststroke - which he holds the Olympic, Commonwealth Games and world championship titles in - curiously left off from the program.
The USA recovered from their slow start to end the night with a 159-148 lead in Duel in the Pool points.
The second night of Duel in the Pool will include the men's 4x100m freestyle that sparked much of the rivalry between the swimming powerhouses, as well as a world-first with a mixed relay that includes able-bodied and para-athletes.
