China's young swimming dynasty showed signs of cracking under the strain of the drug controversy that has shaken the World Championships as their swimmers were humiliated in Perth yesterday.

Dubbed the new golden flowers before they arrived, the women were more like wall-flowers as they faded into the background on the second day of competition.

None of their top women reached a final, and most swam seconds off the times they set at the national championships in Shanghai last October when the suspicions about drug abuse resurfaced.

The day, instead, belonged to the United States and Australia. World record holder Tom Dolan and unheralded Kristy Kowal powered the US to the top of the medal table with victories in the 400 metres individual medley and 100 metres breaststroke respectively, while the Australian men's team grabbed gold in the 200 metres freestyle relay.

Dolan's win was expected, but Kowal's was a stunning win. The Americans were bidding for a third gold on the night, but were blown away by Australia, who stormed to victory in championship time.

The Australians' stormed away for a 4.29-second winning margin in 7:12.48, blitzing the Netherlands (7:16.77) and Britain (7:17.33) with the fancied US trailing in fifth place behind Germany.

The win gave home favourite Michael Klim a second gold medal of the championship following Monday's victory in the 200 metres freestyle. Klim will try to upset world record holder Alex Popov in this morning's 100 metres freestyle.

Britain's freestyle quartet lived up to their third-placed ranking to take the bronze in the dramatic final, breaking the national record they set when striking gold in last summer's European Championships.

Dolan (22), led from after the first butterfly leg to beat European champion Marcel Wouda of the Netherlands and win 4:14.95 - outside his world record of 4:12.30.

"This was a big pride race for me," Dolan said. "Some people doubted me after I finished '97 ranked fourth in the world, but this sets me up in the world that I am the world's best all-round swimmer and I'm not ready to give that title up," he added.

It was an euphoric night for Kowal, a 19-year-old student from Georgia who came in at 1:08.42 to touch out Australian number two Helen Denman (1:08.51) and Canadian Lauren van Oosten (1:08.66).

"I'm feeling sheer and utter joy," said Kowal. "This is the absolute highlight in my life - it is a personal best, it is a gold medal, it is everything."

Earlier, Costa Rican Claudia Poll picked up the missing world gold medal for her trophy cabinet with victory in the 200 metres freestyle to go with her Atlanta Olympics gold.

The Chinese women's team, who had been predicted to repeat their rich harvest of 12 out of 16 golds from the last World Championships in Rome in 1994, have managed to take just one of the four golds on offer so far.

They have also won a solitary bronze as the controversy surrounding disgraced swimmer Yuan Yuan and her coach, Zhou Zhewen, continues with FINA, the world governing body, still to announce their fate.

Shan Ying - coached by Zhou, who admitted packing the illegal human growth hormones that were discovered in Yuan's baggage at Sydney airport - was hopelessly off the pace in the 200 metres freestyle heats. Shan, who had attacked media coverage of her team after winning that bronze in the 100 metres freestyle yesterday, finished 32nd overall, nearly 10 seconds off her best.

Team-mate Wang Luna, second in the world last year, was over four seconds off her expected pace to only reach the consolation final with the 10th fastest time.

In the 100 metres breaststroke, Wang Wei - ranked third in the world on last year's times - finished with the 29th fastest time. Zhang Yi, ranked fourth, was 16th overall.

As FINA's doping panel failed to deliver its verdict again yesterday, it was revealed that the vials seized from Yuan last week contained unadulterated human growth hormone.

The Australian sports minister, Andrew Thomson, said that a sample testing of two of the 13 vials of the performance-enhancing drug that were confiscated matched the manufacturers' specifications.

"Two vials were tested against vials of the real thing (supplied by the manufacturer) and the two vials were exactly the same," said Thomson.

The secretary of FINA, Gunnar Werner, said the concentration of the human growth hormone in the vials could indicate whether the dosage was enough for the entire Chinese team or just for one swimmer.

But an Australian Sports Commission spokeswoman said the testing report, which has been passed to the doping panel, made no conclusions on dosage.

Finally, back it the pool in the evening, a goal five seconds from time clinched Yugoslavia a 6-6 draw with bitter rivals Croatia in the second round of the water polo competition.

Tensions had been running so high that the crowd was under police guard following disturbances between rival sections of fans in previous matches.

European champions Hungary maintained their unbeaten run with a 17-3 win over Kazakhstan and Olympic champions Spain set up their match against the US today with a 15-8 win over Slovakia. The Americans beat Greece 32.

Italy edged out Russia 8-6 after leading 8-3 after the third period and now face Croatia and Kazakhstan in their next two matches. Australia beat Brazil 9-2.