Australia's evergreen diving star Melissa Wu has endured a rare off-day at the world aquatics championships in Doha, finishing last of the 12 competitors in a 10 metre platform final dominated again by two of China's brightest Olympic stars.

In 2021, Wu had finished third behind the then prodigious 14-year-old champion Quan Hongchan and 15-year-old Chen Yuxi in the Tokyo Olympic final but less than three years on, the teenage pair repeated the dominant one-two on Monday while Wu simply struggled, nowhere near her best.

Wu, now 31 and comfortably the oldest diver to qualify for Monday's final in Qatar, has had a lot of fitness struggles since her Japanese success story, suffering a well-publicised back injury during filming for the reality quasi-military training TV show, SAS Australia.

The Sydneysider subsequently bounced back with a 10m synchro platform gold at the 2022 Commonwealth Games but the serial medallist, having qualified in eighth in the morning for the final, had a disastrous start in the afternoon showdown, when her first of five dives was adjudged the worst of all 12 finalists.

Playing catch-up, she only picked up an even lower score on her penultimate dive, effectively consigning her to last place.

Her final total of 267.10 was more than 104 down on her Tokyo Olympics score. In Japan, she had finished 94.8 behind Quan; in Doha, she was 169.15 adrift of the now 16-year-old champion, who had one spectacular dive rewarded with four judges awarding her a maximum 10.

Chen, now 18, was just 8.45 points down on her teammate, while Britain's Andrea Spendolini Sirieix was a distant third on 377.10.

Twins Wang Liuyi and Wang Qianyi had earlier demonstrated China's brilliance in artistic swimming too, as the 27-year-olds teamed up to capture the women's duet technical gold.

The pair have now combined for eight golds over their world championship careers, having also been in the victorious acrobatic team on Sunday.

In the water polo, Australia's men suffered an early setback, losing their opening game 13-8 to Croatia, having effectively blown any chance after they went 7-1 down.

Tim Hamill, the Sharks' head coach, conceded: "The first half was very disappointing for us.

"I'm not sure whether the moment got to us, whether in our heads a little bit, nerves, so we will look at the game this afternoon and assess all that ... but we need to start our game much better."