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.
