Australia's Mollie O'Callaghan finished with a flourish to break the longest-standing world record in women's swimming, claiming the 200 meters freestyle title in a time of one minute, 52.85 seconds at the World Aquatics Championships on Wednesday.
O'Callaghan, 19, broke the performance-enhancing bodysuit era mark of 1:52.98 set by Italian Federica Pellegrini at the 2009 worlds in Rome, and was 0.16 seconds ahead of silver medalist Ariarne Titmus of Australia in an extraordinary final.
Teenager Summer McIntosh of Canada was 0.80 seconds behind to take bronze in a world junior record time.
Olympic champion Titmus had blazed to the 400m freestyle title on Sunday to erase 16-year-old McIntosh's mark and was primed for another record after topping the semi-final time sheet despite not going full tilt.
But it was O'Callaghan who made light of a knee issue that she suffered before the meet to take charge of a tight race at the end and upstage her illustrious compatriot, with China's Yang Junxuan not defending the title she won in Budapest.
"I'm absolutely excited. I wasn't expecting that at all entering this," an emotional O'Callaghan, who shed tears in the pool after her victory, told Channel Nine.
"I just wanted to have fun and just give it a crack. I was really nervous leading up to this, because I didn't know how I was going to race.
"The lead-up to this has been so up and down like a roller-coaster, just with injury and then coming off trials and all that. Just to do that, I just think is incredible and I'm excited for what else I can do."
Hungary's world record holder Kristof Milak was absent from the men's 200m butterfly that followed, as the Olympic and world champion skipped the meet saying that he was not physically or mentally in a position to compete.
Frenchman Leon Marchand made the most of Milak's withdrawal to capture his second gold of the championships after his world record effort in the 400m individual medley.
The 21-year-old touched the pad in 1:52.43, with Poland's Krzysztof Chmielewski 1.19 seconds away for silver, while local favorite Tomoru Honda delighted home fans at the Marine Messe Fukuoka Hall with bronze.
Another gold
China's Qin Haiyang also added another gold to his tally at the championships in the men's 50m breaststroke, after securing the title over 100m earlier this week.
The 24-year-old had gone quickest with a new Asian best of 26.20 seconds in the preliminary event and came home in 26.29 in the final to edge American Nic Fink who was 0.30 seconds slower. China's Sun Jiajun rounded off the podium in 26.79.
Britain's triple Olympic champion Adam Peaty, who holds the world record of 25.95 seconds in the event, skipped the meet for mental health reasons after also missing the previous edition with a fractured bone in his foot.
His absence was a blow to Britain's hopes of swelling their gold medal tally after Matthew Richards opened their account by leading a one-two in the men's 200m freestyle on Tuesday.
Australia lead the medals table with six golds, ahead of China with four and the United States with three.
Ahmed Hafnaoui put Tunisia on the board by winning the men's 800m freestyle race earlier in the day, claiming gold in a time of 7:37.00.
Sam Short of Australia was 0.76 seconds behind the winner to bag silver, while Olympic champion and 2022 gold medalist Bobby Finke of the US was 1.67 seconds away for bronze.
A dominant Chinese team then denied the US a third world title in the mixed 4x100m medley relay, cruising to victory in 3:38.57, with Australia almost half a second behind.
The Americans had to be content with bronze.
