The stacked Australian squad made a winning start to the world junior athletics championships in Lima with a first global relay title in 26 years in the mixed 4x400m event.
The team of 2023 women's Stawell Gift champ Bella Pasquali, Sophie Gregorevic, Jordan Gilbert and Jack Deguara clocked a winning time of three minutes 19.27 seconds.
The minor medals went to Poland and China.
Anchor runner Gregorevic described the victory as "a shock, but really a dream come true".
"I feel so honoured to put on my national colours and run at a world event, and I'm so happy that we have been able to achieve the result that we have. I hope that there is many more like it in the future," Gregorevic said.
In other action, Aleksandra Stoilova - who was a member of the 4x100m relay squad at the Paris Olympics - became the first Australian since Sally Pearson in 2004 to reach the women's 100m final at the global under-20 championships.
Stoilova held her nerve to sneak into the final on Wednesday (Thursday AEST) by one-hundredth of a second.
The Clemson University student clocked 11.58.
"College is good for this type of championships because you have heats, semi-finals and the final - it's good practice. Last World Juniors, just running the heats of the 4x100m and not the final, it was a big motivation for me to push into the individual events this time around," Stoilova said.
Reigning Australian senior 100m champ Sebastian Sultana missed out on a berth in the men's final after clocking 10.52 in his semi.
Gabrielle Schmidt was a creditable seventh in the women's 5000m in a PB of 16:10.87 in a race where the top five all hailed from east Africa.
Paris Olympics semi-finalists Peyton Craig and Claudia Hollingsworth both cruised into the semi-finals of their respective 800m events.
