Australia stunned the United States in the men's 4x100m relay yesterday, ending a run of three straight wins and handing Michael Phelps a slow start to his last world championships.
James Magnussen had the better of Phelps in the first leg and Australia's Matthew Targett, Matthew Abood and Eamon Sullivan held off France to finish in 3mins 11.00secs. The US were third.
It was a resounding finish to the first day of pool competition after China sealed the first 10-title diving sweep and South Korea's Park Tae-Hwan won his 400m freestyle duel with the Chinese athlete, Sun Yang.
The Netherlands successfully defended their women's 4x100m crown and Italy's Federica Pellegrini sealed her second successive 400m freestyle world title.
But it was Australia, gunning to improve on their disappointing performance in Rome in 2009, who stole the show and gave the 14-time Olympic gold medallist Phelps a bitter start to his final year in the sport.
"It's tough not starting off how we want to," said Phelps, who will retire after the London Olympics.
"I said I wanted to be faster than I was last year, and I was faster than I was last year.
"It stinks, but I think it will give us a little bit of motivation for the rest of the meet."
Earlier, Shanghai's purpose-built Oriental Sports Centre witnessed the final act in China's 10-out-of-10 diving performance, which put the seal on a decade of dominance.
Qiu Bo epitomised China's diving mastery as he collected 585.45 points in the final, more than 40 ahead of American David Boudia with Germany's Sascha Klein taking bronze.
It was one of only two individual events in which China did not seal both gold and silver, underscoring the wide margin they enjoy over their closest rivals.
The Olympic champion Park sneaked down the outside lane almost unnoticed to win his hotly anticipated 400m freestyle shoot-out with Sun, the quickest man this year.
Park had his nose in front early on and finished nearly a length ahead of Sun, 19. The defending champion, Germany's Paul Biedermann, was relegated to bronze.
"I am glad to swim in lane one, which allowed me to fully concentrate on my own tempo and not to get distracted by the competition," said Park, who also won the title in 2007.
Earlier, the Brazilian sprinter, Cesar Cielo, the main figure in a doping row, pleaded with his critics to leave him alone.
He insisted he was just "here to swim" as Phelps and others voiced unhappiness that he is swimming here despite failing a drugs test.
"I don't know what else they want from me," Cielo said. "I'm a swimmer, I'm here to swim. There's nothing else I can do."