Ian Thorpe scored a comprehensive victory over his Olympic nemesis Pieter van den Hoogenband and Michael Phelps set a majestic world record at the world swimming championships on Tuesday.

Thorpe retained his 200 metres freestyle title to take his record haul of world championship gold medals to 10 -- two in 1998, an unprecedented six in 2001 and two in the first three days of action in the Palau Sant Jordi pool.

Phelps lowered his own 200 butterfly world mark by more than half a second, sweeping away from his semi-final rivals in one minute 53.93 seconds to beat the 1:54.58 mark he set in winning the title at the last world championships in Japan in 2001.

Thorpe, who won the 400 freestyle world title on Sunday for a record third time, trailed his Dutch rival at the 100-metre mark but had hit the front by the end of the third length and surged away to win in one minute 45.14 seconds.

Van den Hoogenband, who was also well beaten by Thorpe at the 2001 world championships, had to settle for silver again, touching more than a second adrift in 1:46.43.

Grant Hackett, silver medallist behind team mate Thorpe in the 400 freestyle for the third successive time, took the bronze in 1:46.43.

AUSTRALIAN DEFEATS

Fellow Australians Matt Welsh and Leisel Jones, heady world record breakers on Monday, came down to earth with a bump as both were beaten in finals.

Welsh, who scored an upset victory in world record time in Monday's 50 butterfly final, lost his 100 backstroke world crown to American Aaron Peirsol, whose sister Hayley had earlier achieved a silver medal in the 1500 freestyle. Welsh shared silver with Russia's Arkady Vyachanin.

Seventeen-year-old Jones, who broke the women's 100 breaststroke world record in Monday's semi-finals, found herself left with the bronze in the final behind China's Luo Xuejuan -- the first woman to retain the world title in the event -- and American Amanda Beard.

Germany celebrated double gold success for their women, with Hannah Stockbauer, Sunday's 400 freestyle champion, retaining the 1500 freestyle title and Antje Buschschulte winning the 100 backstroke.